Yield: 4 servings
1 tablespoon butter, plus more for soufflé dish
Sugar, for soufflé dish
2 tablespoons all-purpose flour
½ cup whole milk
1 cup mashed sweet potatoes, peeled and cooked
3 large eggs, room temperature, separated
¼ cup maple syrup
¼ teaspoon ground nutmeg
¼ teaspoon ground cinnamon
½ teaspoon fresh orange zest
½ teaspoon salt
Whipped cream (optional)
Preheat oven to 375°. Butter a 1½-quart soufflé dish; dust with sugar.
In a medium saucepan, melt 1 tablespoon butter over medium heat. Whisk in flour and cook, stirring, until golden, about 2 minutes. Gradually whisk in milk; simmer, whisking constantly, until thickened, about 1 minute.
Remove from heat; mix in sweet potatoes and egg yolks. Stir in maple syrup, nutmeg, cinnamon, and orange zest. Set aside.
In a small mixing bowl, use an electric mixer to beat egg whites with a pinch of salt until stiff peaks form. Whisk ¼ of whites into sweet potato mixture; using a rubber spatula, gently fold in remaining whites. Pour mixture into prepared dish; place on a rimmed baking sheet. Bake until top rises and is puffed, 35 to 45 minutes. Serve immediately, with whipped cream, if desired.