Peel sweet potatoes and chop them into 4 pieces. Place sweet potato chunks into a pot and fill it with water, just enough to cover the potatoes.
Bring water to boil and cook potatoes until fork-tender. Strain all the water out of the pot and let potatoes cool for a few minutes.
Add butter, eggs, milk, brown sugar, and vanilla extract and mash it all together using a potato masher.
Grease a 9×9 casserole pan with some butter all over the bottom and up the sides. Spread potato mixture evenly in the pan.
Preheat the oven to 350°.
Pecan Crumble Topping:
Combine flour, brown sugar, cinnamon, and chopped pecans in a mixing bowl and mix until all evenly incorporated.
Pour in melted butter while stirring with a fork. Continue to cut and stir with a fork until coarse crumbs form. The topping should look like crumbs, not paste.
Spread the pecan topping over sweet potatoes evenly and bake the casserole for 40-45 minutes.
Marshmallow Topping Option:
For the marshmallow topping, you can choose to add marshmallows on top of the crunchy pecan topping or just stick to simple pecan and marshmallows.
Spread pecans (or pecan crunch topping) over the sweet potato filling and bake for about 30 minutes.
Take the casserole out and spread marshmallows over the top. (If you want to get super creative, sprinkle a little bit of coarse salt on top as well.)
Bake for another 10-15 minutes, until the marshmallows are golden brown.
Video
Notes
Nutrition NOTE: nutrition is calculated for Sweet Potato Casserole with Pecan Crunch Topping. Gluten free - to make this casserole gluten free, use gluten free all purpose flour in the pecan crumble topping. Make Ahead:Option 1: Prepare sweet potato filling and spread it in the casserole dish. Cover the dish air-tight with plastic wrap or aluminum foil and refrigerate until ready to bake. When ready, prepare the topping, spread it over the sweet potatoes and bake at 350° for about 45 minutes. Option 2: Casserole can also be completely baked and stored in the refrigerator. Bake the casserole as directed in the recipe and let it cool to room temperature. As soon as it’s cooled, cover it air-tight and store in the refrigerator.