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