Preheat the oven to 425°F and line a baking sheet with foil. Wash and dry the outside of the sweet potatoes then wrap them in aluminum foil and place them on the prepared baking sheet. Place the potatoes in the oven and bake for 1 1/2 hours, until the potatoes are tender and easily pierced with a fork.
4 large sweet potatoes
Remove the sweet potatoes from the oven and allow to cool until you can remove the skins without burning your fingers, about 30 minutes. Remove the sweet potato skins before proceeding with the recipe.
Preheat the oven to 350°F. Grease a 9x13-inch baking dish with cooking spray and set aside.
In the bowl of a mixer or with an electric hand mixer, beat the cooked sweet potatoes on medium-high until they become smooth, about 2 minutes. Add in the butter, brown sugar, granulated sugar, and cinnamon and mix until fully combined.
½ cup unsalted butter, 1 cup brown sugar, ¼ cup granulated sugar, 2 teaspoons ground cinnamon
Continue beating and add in the eggs, milk, vanilla, and salt. Beat on medium-high until the mixture is smooth and all of the ingredients are fully incorporated. Pour the mixture into the prepared baking dish.
2 eggs, ½ cup whole milk, 2 teaspoons vanilla extract, ¼ teaspoon salt
Now, make the topping. In a medium bowl, whisk together the brown sugar, flour, salt, and cinnamon until well combined. Add the pecans and toss to coat. Stir in the melted butter and stir until the butter is absorbed, forming a sort of crumble/dough mixture. Scatter the topping evenly across the top of the sweet potato mixture.
½ cup light brown sugar, ½ cup all-purpose flour, ¼ teaspoon kosher salt, ¼ teaspoon ground cinnamon, 1 ½ cups pecan halves, 5 Tablespoons unsalted butter
Place the soufflé in the oven and bake it until the center of the soufflé is set and does not jiggle when tapped, about 45 to 55 minutes.
Remove from the oven and let cool in the pan for 10 minutes before serving.