Improved sweet potato & marshmallow casserole! / Sweet potato souffle with sour cream marshmallow, scallion, and roasted garlic

Sweet potato souffle with scallion and roasted garlic, topped with toasted sour cream marshmallow

Most Thanksgivings, I like to try and put an updated spin on classic dishes.   This year, I decided to tackle what I think is the worst of all traditional Thanksgiving dishes, sweet potatoes and marshmallow casserole.  Personally, I think this composition doesn’t make much sense, since it pairs sweet with more sweet, and is served as a appetizer/side, rather than a dessert type dish.  I decided to update this dish by making the pairing more like something that hopefully we can all agree makes more sense – a loaded baked potato.  Follow these links to skip to just the recipes for sour cream marshmallows and for sweet potato soufflé.

Rather than pairing the sweet potato with sweet marshmallows, I decided a savory appetizer would require a savory marshmallow.  For a baked potato-inspired dish, it would make sense to have the marshamllows be sour cream flavored.  Making savory marshmallows really is as simple as mixing in a few tablespoons of a savory flavoring component into the mix of a normal marshmallow recipe.  However, in the course of this project I also discovered a way to make the procedure for making marshmallows significantly safer and faster.

Left: corn syrup mixed with sugar to ~85% by weight sugar. Center: blooming gelatin. Right: mixed sugar solution and dissolved gelatin, with sour cream

Left and center: sour cream marshmallow mixture after 10 minutes whipping, coated with corn starch and powdered sugar. Right: squares of sour creammarshmallow cut out

The traditional recipe for making marshmallows involves 1) blooming gelatin, 2) bringing a corn syrup/sugar syrup to 240 degrees Fahrenheit, 3) carefully adding the super-hot syrup to the gelatin in a stand mixer and whipping for up to 15 minutes, and 4) cooling and cutting the marshmallow mixture.  After analyzing a number of marshmallow recipes, I found it odd that all required the second step of heating sugar syrups to a set temperature (typically necessary in confection making in order to reach a precise/consistent sugar concentration, in this case, ~85% sugar by weight), but some recipes added this sugar syrup to unmeasured or unspecified amounts of water used for gelatin blooming in step 1.  This suggests that while having a low water content in marshmallows is important, a range of water content would produce acceptable marshmallows.  Since the step for heating syrups was clearly not very important for acquiring precise sugar concentrations, the only other purposes working with a heated syrup would serve would be 1) ease of dealing with a slightly lower viscosity fluid, and 2) heat from the syrup would aid in dissolving gelatin.  Ultimately, I found that the traditional step of heating sugar syrups to 240F could be eliminated by calculating and preparing a sugar solution of desired final concentration (85% sugar by weight), and applying low level heat to dissolve gelatin separately.  The 85% sugar solution and dissolved gelatin could be mixed with flavorings (sour cream in this case), whipped, cut, and cooled just as in traditional recipes.  This modification to the traditional procedure eliminates the time needed to heat the sugar syrup, and eliminates risk of splashing extremely hot, skin-burning syrup around your kitchen.

Left two: Roasted sweet potato blended with green onion, roasted garlic, brown sugar and butter. Center: Making a roux for bechamel sauce.  Right two: Finished bechamel sauce

Leftmost: Combining sweet potato blend and bechamel sauce.  Center-left: Stiff-peak meringue. Center-right: souffle mix in ramekin. Rightmost: Finished sweet potato souffle with green onion and roasted garlic

As opposed to the traditionally dense sweet potato mash in a sweet potato and marshmallow casserole, I thought the dish could benefit from some added variety of flavor and lightness.  For this reason, I thought a great accompaniment to the sour cream marshmallows would be a sweet potato soufflé.  For this, I basically used a scaled down version of Emeril Lagasse’s recipe, with one clove of roasted garlic and a tablespoon of finely chopped green onions mixed into the sweet potato puree.  Once removed from the oven, these soufflés can be topped with the savory marshmallows and torched for even more complex caramelized flavor.  Enjoy, and happy Thanksgiving! 

Another view of the savory sweet potato souffle with toasted sour cream marshmallow

Halloumi cheese waffle and poached pear / Broader waffle maker applications part 1!

It’s been another few months without articles, but more will be coming soon! I’ve been busy recently with my PhD thesis proposal (it went fine, btw).  In the next couple articles, I’ll be investigating interesting applications of a heavily underrated piece of kitchen equipment – the wafflemaker!

Left: Halloumi cheese waffle. Center: Poached pears marinating/macerating in a wine syrup. Right: Poached pear with gelato and (unpictured) halloumi cheese waffle

The unique advantage of a waffle geometry is its increased surface area to volume ratio, compared to a flat square or circle of similar dimensions.  The Good Eats episode about waffles does a good job of discussing some of the advantages that come from this property, for instance, waffle irons were used to mold the first soles of running shoes (the beginning of Nike).  For regular edible waffles, the unique benefits are the ability to retain wells of syrup and to have lots of fried crunchy/crisp exterior, with some soft interior.  These seem like properties that could easily extend to many other fried goods, wouldn’t you think?

Fried halloumi cheese slices - very crispy, but little chewy/soft interior.  If cut into cubes, they require 5 manipulations to fry each side

One of the first foods I thought could benefit from wafflization was halloumi cheese.  Halloumi cheese is a special type of brined cheese, salty like feta but softer and creamier, that is known for its ability to be fried or grilled and retain its shape while gaining a crispy exterior.

Left: Comparison of percent by weight of fat, protein, and water (the remaining weight out of 100g that was not fat or protein) between 5 cheeses categorized as high melting point and 5 cheese categorized as low melting point.  No significant differences in composition were observed.  Right: Comparison of salt content between high melting point and low melting point cheeses in 100g of cheese.  The difference was found to be significant at p<0.01 using 1-way ANOVA.

I’ve seen many peoples’ websites attempt to explain why this is the case, but have come across a surprising range of explanations.  While many of these reasons (moisture content, protein content, type of fat, salt content) all seem to be plausible reasons, when analyzing the composition of several high-melt point (halloumi, feta, parmesan, cotija, and aged asiago) and low-melt point cheeses (mozzarella, swiss, cheddar, camembert, and brie), I found that only salt content seemed to significantly contribute to the melt-point (data courtesy of http://www.sargentofoodservice.com/trends-innovation/cheese-melt-meter/ and www.fatsecret.com, acid-curdled, reduced fat, and added fungal culture cheese excluded from analysis, n=5 for each, P<0.01 for salt content).  Salt molecules present within a cheese are believed to interact with the cheese protein network – with more salt keeping these networks stable when they would normally fall apart due to applied heat.  Therefore, I believe that the interesting properties of halloumi are due to its relatively high salt content from brining.

Left: 1/4-1/2" slice of halloumi on medium heat in waffle maker.  A crispier exterior is attainable by brushing with oil and/or using higher heat.  Center: After 2 minutes or less, the halloumi cheese gains a crisp exterior.  Right: The interior of the halloumi cheese waffle is airy, soft and light due to small air pockets in the cheese.

By brushing, dipping, or coating with oil, a much crispier exterior than what I have pictured here is possible.  Frying in a waffle maker requires as little as 2 minutes (depending on your settings), without the need to turn halloumi cubes 5 times (for all sides of a cube), and yields a crispy on the outside, light and airy on the inside cheese waffle.  I didn’t think of this till later, but it would also go well with a nice poached pear.

Variations on xiao long bao (Soup Dumplings) / Vegetarian xiao long bao with carrot-ginger soup and samosa filling

It's been a while since my last post, I've been a bit busier and also took a while to think of a new project.  I decided to try making xiao long bao (XLB), or Chinese soup dumplings.  These tasty dumplings are usually filled with a ground pork/scallion filling as well as a rich broth.  What's interesting about the process of making XLB is that it uses gelatin to set the broth into a solid state, which can be easily handled and used to fill the dumpling.  This same technique has been used in a range of other recipes and in restaurants to make liquid-filled ravioli (like the Black Truffle Explosion at Alinea).  Given how versatile/adaptable the process for making XLB is, I was surprised that there haven't been many varieties of XLB produced.  To demonstrate the flexibility of this procedure, I decided to make a vegetarian xiao long bao with a samosa filling (curry potato and pea) with a complementary carrot-ginger soup.

Left: Carrots and onions for boiling in a pot. Center: Softened carrots pureed with immersion blender, cream and ginger powder added. Right: Carrot ginger soup gel after Vegan Jel added to 2X diluted soup, 

In order to create a soup gel, I used the "Vegan Jel" product by Natural Desserts, which is created from vegetable gum.  I chose this as opposed to other vegetarian gelling agents (which you can read about here) because it's substitution for gelatin in recipes was fairly straightforward (1.5 tsp substitutes for 1 tsp gelatin), and because it was claimed to have a similar melting point to gelatin.  In making the soup gel, I found that I had to first cook the soup down to my desired consistency, then dilute it with one equal part of water.  Without this step, the soup dries up during the dumpling steaming step, since a fair amount of moisture is lost.

Left: Mashed boiled potato. Center: Mashed potato with garam masala, coriander powder and cardamom powder. Right: Curried potato filling fried in a pan with onion and mixed with peas

Several recipes for making samosa filling involved cooking down onions with garam masala, then mixing in mashed/boiled potato.  I found that you get much more control over the flavor by splitting your mashed/boiled potato into two batches - to one which you add garam masala, corriander powder, cardamom powder and salt to to taste, the other unseasoned batch you reserve for correcting mistakes (can mix in if any one flavor seems too strong and then adjust seasoning again).  For more texture, it was better to leave some larger not-fully-cooked chunks of potato.

Left: Filling a handmade dumpling skin with gelled soup and samosa filling. Right: pleated and filled xiao long bao 

With a 2X diluted and gelled soup, I found that the ideal ratio of soup:filling was close to 2:1.  At around 1:1 or less, there wouldn't really be a noticeable amount of soup in the dumpling.

Left: Vegetarian samosa filling and carrot-ginger soup xiao long bao steamed for 10 minutes. Right: Opened XLB

I may add more analysis later on gelling agents and an actual recipe entry.  I would say that the finished product was tasty, although could use some improvement.  A meat-filled dumpling typically has more bite/texture, whereas between the samosa filling, dumpling skin, and soup, there isn't much variety in texture.  A future project may be a soup-filled samosa, which would have the needed deep-fried crunch.  Another possibility would be to have a mushroom-based filling for more bite, and a gelled mushroom or vegetable broth.

The Greatest Cupcake II / Chocolate cupcake with white chocolate, cherry & moscato mousse, spun sugar

I've been thinking for a while now that my last cupcake article was not so visually impressive.  I feel like the blog has come a ways since then, so at the very least I could make a better looking (and hopefully better tasting!) cupcake than before.  Also, I thought it would be fun to decorate cupcakes with my girlfriend on Valentine's, so I focused on preparing components that would definitely have an impressive visual factor and incorporate some of her favorite things.

In the previous cupcake article, I had tried to make a white chocolate cherry mousse, but have to admit it didn't really have the appearance, texture, or flavor I wanted.  With a bit more know-how, I wanted to give it another try.  I was also tempted to buy a whippet/whipped cream dispenser, but couldn't really justify the expense - while they make mousse-making extremely fast and easy, most interesting things that can be done with a whipped cream dispenser can be done without one with just more time and effort.  Maybe in another article.

White chocolate mousse

The construction:

Devil's food cake again for the base.
White chocolate mousse made like before, but I've learned now that to avoid lumps in the mousse, just lightly heat the chocolate/butter or chocolate/egg mixture after mixing
Black cherry moscato syrup made by taking ~3 cups fresh cherries and heating on high heat with 1/2 cup sugar, 1-1/4 cup moscato.  After the cherries had all softened (~20 minutes), the mixture was pressed through a strainer and reduced further, with 1 tbsp moscato mixed with 2 tsp cornstarch added at the end for more thickness and more flavor.  The finished syrup was kept separate from the mousse to preserve its color - mixing it in too thoroughly can result in an unappetizing very pale pink color.
Spun sugar made by heating 6/10 cup sugar with 1 tbsp water and 1 tsp moscato until an amber color was reached (probably corresponding to the "hard crack" stage or beyond, given that some caramelization has occured).  Once the syrup flowed off a fork/chopsticks in thin ribbons, it would be quickly crisscrossed over an egg brushed with oil - an egg for a nice ellipsoid shape, and oil to help remove the hardened sugar cage.  If you decide to try this out on your own, be careful of burns!

Left: an especially fine sugar cage. Center: crisscrossing syrup over an egg on parchment paper.  Right: a collection o spun cages, thicker ones transported a bit better

Foolproof, enhanced, scalable beef Wellington recipe / Deep fried beef Wellington!

Deep-fried beef Wellington

Beef Wellington is notorious for being one of the most difficult dishes for a home cook to attempt. It consists of a beef tenderloin (or filet mignon) wrapped in puff pastry, with optional fillings like mushroom duxelle (dried mushroom spread), pate, prosciutto, or crepes, pretty much a fancy man's hot pocket.  The considerable difficulty lies in:

• making puff pastry (which can be avoided by using less-tasty pre-made frozen puff pastry), 
• constructing the wellington to prevent soggy crust (despite recipe suggestions to add prosciutto or crepes, the underside seems to inevitably become soggy or crushed during the prolonged baking period)
• timing the cooking such that the beef tenderloin and puff pastry are done at the same time.

To address the difficulty in cooking time and crust construction, I decided to take a new approach.

I've had this idea ever since my cronut article to look at more interesting applications of deep fried puff pastry.  Deep frying would be beneficial since

• the entire Wellington is cooked homogeneously and rapidly, preventing any liquid buildup on a bottom crust
• the beef tenderloin could be cooked separately and well in advance to its desired temperature before construction of the Wellington, due to the rapid cooking time
• individual-size or mini beef Wellingtons could be made with a finished crust and beef anywhere from rare to well-done, another added benefit of rapid cooking time

Top left: MATLAB PDEtool simulation of a fried cronut, using the same parameters as found in the ABAQUS simulation in the cronut article, for validation.  The internal temperatures (in Kelvin) are similar.  Top right: model of a beef Wellington fried at 370 degrees Fahrenheit for 4 minutes.  Thermal parameters for puff pastry were identical to those used for croissant dough in cronut model.  Beef and oil thermal properties from Advances in Deep-Fat Frying of Foods, edited by S Sahin, SG Sumnu 2009 on Google e-books.  Bottom left & right: view along the x- and y-axes respectively of the top-right figure.  The puff pastry was modeled to be 1 cm in thickness, beyond that the meat's temperature does not rise above ~150 degrees Fahrenheit, while the puff pastry has all reached temperatures over 150, which corresponded to 'done' in the cronut experiment.

First, I wanted to model the cooking process to make sure I didn't waste a whole bunch of time and money.  Using MATLAB PDEtool, I was able to determine that 4 minutes of frying should be sufficient to cook the puff pastry crust without substantially changing the done-ness of the beef interior.

Left: Seared beef tenderloin. Center; Beef tenderloin roasted at 450 degrees to an internal temperature of 125.  Instead of an expected 10 degree increase in carryover, this cut only reached a maximum temperature of about 130, or on the rare side of medium-rare.  Right: wrapping beef tenderloin, coated in dijon mustard, with mushroom duxelle and prosciutto

I proceeded to sear then roast a cut of beef tenderloin to an internal temperature of ~130 degrees Fahrenheit, for medium rare, on the rare side.  The beef was then wrapped in a baby portobello mushroom duxelle and prosciutto.

Left: Wrapped beef tenderloin, normally this is done with plastic wrap, but I didn't have any so I used a cut up shopping bag.  Center: Wrapping a chilled and wrapped beef tenderloin with an eggwashed layer of puff pastry.  Right: Eggwashed beef Wellington.  The scoring is not advised if deep-frying. 

The wrapped tenderloin was then encased in an eggwashed layer of puff pastry.  This was deep fried at ~370 degrees Fahrenheit for 4 minutes, rotating halfway through. (CAUTION: use protective eyewear and gloves when deep frying something of this size, be very careful sliding the wellington into hot oil to avoid splashing).  The crust came out crisp and flaky, while the interior remained medium-rare.  Served with roasted Brussels sprouts and a parsnip puree.

Left: Beef Wellington deep fried at 370 degrees Fahrenheit for 4 minutes total, rotating halfway through.  Center: Finished deep fried beef Wellington, resting for 10 minutes is sufficient.  Right: Sliced beef Wellington with roasted Brussels sprouts and parsnip puree.  The interior of the Wellington is seen to be still medium-rare, on the rare side.

To confirm that mini wellingtons could be made, I cooked some tenderloin scraps to medium, wrapped them in puff pastry, and fried them as well.  The interior remained medium.

Left: A tenderloin scrap, cooked to medium.  Center: Tenderloin scrap wrapped in puff pastry and fried 4 minutes at 370 degrees.  Right: Sliced mini beef Wellington, still medium with done and flaky crust

By comparison, the baked beef wellington came out at approximately the same done-ness, but requires a good half hour or more resting to not lose a lot of its juices, and to cool down enough to eat.  Also, the bottom crust was tasty, but crushed and not flaky.

Left: Baked beef Wellington. Right: Sliced traditional beef Wellington after only 10 minutes resting, clearly lots of juices were lost, and it was very hot to handle.  The bottom crust is seen to be soggy and crushed, despite the use of prosciutto and a fairly dry mushroom duxelle.