Preheat oven to 400 F. Poke a few holes in each sweet potato with a fork and spray with some oil. Place the sweet potatoes on a baking sheet lined with foil or parchment paper for easy clean up. Bake in the preheated oven for 30 - 40 minutes until soft.
4 - 6 sweet potatoes
In a large bowl or in a stand mixer, scoop out the flesh of the sweet potatoes (discard the skins). Add the egg, maple syrup, ½ teaspoon of the cinnamon, nutmeg, and sea salt. With the paddle attachment or a hand mixer, beat the sweet potatoes until smooth.
1 egg, ⅓ cup maple syrup, 1 teaspoon cinnamon, ¼ teaspoon nutmeg, ¼ teaspoon sea salt
Spread the sweet potato mixture into a greased 9 x 13 inch baking dish. Set aside.
In a bowl, add the melted butter, rolled oats, pecans, brown sugar, and remaining ½ teaspoon cinnamon. Mix until well combined. You should have small clumps of oats and pecans and sugar.
5 tablespoon butter, 1 cup rolled oats, 1 cup pecans, ½ cup brown sugar
Sprinkle the oat mixture over top of the sweet potatoes in an even layer. Bake in the oven for 25 - 35 minutes until toasted on top. Allow the casserole to set for at least 20 minutes before serving.