French Savory Sweet Potato Soufflé

Instructions

1. Step 1

   Gather the ingredients.

2. Step 2

   Pre heat oven to 375 F. Brush the inside of a large soufflé or deep casserole dish with 1 1/2 tablespoons of softened butter. Sprinkle the buttered surface evenly with Parmesan cheese and set aside the dish.

3. Step 3

   In a large saucepan over medium heat, sauté the onions and garlic in the remaining butter until they turn translucent and tender. Take care to make sure the onions do not burn.

4. Step 4

   Add the flour and salt to the tender onions and garlic. Cook the flour, whisking constantly, for 30 seconds.

5. Step 5

   Add the milk to the flour and cook, still whisking constantly, for about 4 minutes, until the mixture thickens. This part of the recipe is important to the success of the souffle, so do not rush it.

6. Step 6

   Add the sweet potato puree, dried thyme, and black pepper and continue cooking over medium heat for 1 minute. Remove from the heat and stir in the Gruyere cheese.

7. Step 7

   Whisk 1/2 cup of the hot sweet potato mixture carefully into the egg yolks, and then add the egg yolk mixture back into the hot sweet potatoes, stirring to completely incorporate. Again, take care not to rush this part.

8. Step 8

   Beat the egg whites on high speed until stiff peaks form. Stir 1/3 of the egg whites into the sweet potatoes, and then fold the remaining egg whites into the mixture.

9. Step 9

   Spoon the finished mixture into the prepared dish and bake for 30 minutes, until the sweet potato soufflé is puffed up and cooked through. The soufflé should be served immediately, it will not keep beyond a few minutes out of the oven. Make sure everything is set for the serving before it is removed from the oven.