Preheat your oven to 350°F (175°C). Peel and chop four medium sweet potatoes into chunks. Boil them in salted water for about 15-20 minutes or until they’re tender and easily pierced with a fork.

Drain the sweet potatoes and return them to the pot. Stir in half a cup of unsalted butter, one cup of dark brown sugar, two eggs, and one teaspoon of vanilla extract. Mash until you achieve a smooth, creamy consistency without any lumps.

Spread the sweet potato mixture evenly into a greased baking dish. Use a spatula to smooth out the top, creating an even surface for the delicious toppings.

In a separate bowl, combine one cup of chopped pecans with one cup of mini marshmallows. Sprinkle this delightful mixture generously over the surface of the mashed sweet potatoes.

Place the baking dish in the oven and bake for 25-30 minutes until bubbly and golden brown on top.

Allow the casserole to cool slightly before serving.