gruyère and thyme sweet potato soufflé

If your Thanksgiving dinner needs a facelift, this soufflé is here to help. In my opinion, one of its most refreshing qualities is that it is not covered in marshmallows. If I lost some of you with that last sentence, don’t worry, this soufflé is unique enough that it could be enjoyed alongside your traditional sweet potato recipe and no one would bat an eye. If you are curious what exactly a sweet potato soufflé is, I tell people it’s egg fluffed sweet potato frolicked with gruyère, thyme, and finished off with a crispy layer of parmesan goodness. It’s heavenly, and I can honestly say that it’s my absolute favorite way to eat potatoes. Hands down.



feeds 8 as a side

1 and 3/4 lbs orange sweet potatoes (about 2 medium potatoes)
4 tablespoons unsalted butter, separated (1T is for greasing dish)
2.5 ounces freshly grated parmesan
1 and 1/3 cup finely chopped yellow onion (roughly one medium onion)
3 large garlic cloves, minced
1.5-2 teaspoons chopped fresh thyme
salt and pepper to taste
3 tablespoons all-purpose flour
1 and 1/3 cup whole milk
3.5 ounces grated gruyère
6 large eggs, separated


  1. Preheat oven to 400 degrees F. Line a baking sheet with parchment paper and spear your sweet potatoes with a fork. Cook the sweet potatoes for 1 hour then set aside until cool enough to handle. When cool, scrape off the skins and purée the de-skinned potatoes in a blender or food processor. Set aside and adjust oven heat to 375 degrees F.
  2. Melt 1 tablespoon butter and brush inside surface of a 2 quart soufflé dish (or deep casserole dish), sprinkle ¼ cup of the grated parmesan evenly over the surface of your dish.
  3. Melt remaining butter in a large saucepan over medium heat. Add the onion, garlic, and thyme and sauté for 5 minutes or until onion is translucent and soft. Season with salt and pepper. Add flour and cook for another 2 minutes, stirring constantly. Next, add the whole milk slowly (about 1/3 cup at a time), and after all the milk is added, simmer for 5 minutes stirring frequently (roux will thicken up).
  4. Remove from heat and add gruyère; stir until melted. Add sweet potato and mix well. Taste batter and add salt or pepper to your preference. Next, add egg yolks, one at a time, stirring after each addition.
  5. Beat egg whites with a pinch of salt until stiff peaks form. Fold into sweet potato mixture. Pour into the prepared dish and sprinkle remainder of parmesan cheese on top. Cook at 375 degrees F for 50-60 minutes, until top of soufflé is puffed like a dome and dark golden brown. The souffle is best warm out of the oven, but reheats well and leftovers never get missed at our house.

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