Preheat oven to 400°F (200°C). Pierce sweet potatoes all over with a fork, place on a baking sheet lined with foil, and bake for 45 to 55 minutes until completely tender when pierced with a knife. Allow to cool for 10 minutes, then easily peel and discard the skins.

Reduce oven temperature to 350°F (175°C). Grease a 9x13-inch (or large oval ceramic) baking dish with butter.

In a large mixing bowl, combine warm roasted sweet potato flesh, melted butter, pure maple syrup, heavy cream, beaten eggs, vanilla extract, cinnamon, nutmeg, and sea salt. Whip with a hand mixer on medium speed for 2 minutes until light, fluffy, and completely lump-free. Spread evenly into prepared baking dish.

In a separate medium bowl, stir together chopped pecans, dark brown sugar, flour, cinnamon, and a pinch of salt. Pour in the 6 tablespoons of melted butter and stir with a fork until a fragrant, crumbly, clumpy streusel forms.

Evenly scatter the brown sugar pecan streusel across the top of the sweet potato base, making sure the entire surface is covered in crunchy pecan clusters.

Bake at 350°F (175°C) for 32 to 35 minutes until the sweet potato edges are puffed and gently bubbling and the pecan streusel is fragrant, deep golden, and crisp. Rest for 10 minutes before serving warm!