Step 1

Preheat the oven to 350°F and line a baking sheet with aluminum foil. Wash the potatoes. Place them on the baking sheet and prick each potato several times with a fork. Bake for about an hour or until they are soft and a knife easily slides through the middle of each potato. Allow to cool enough to handle, then peel.

Step 2

Spray a 2-quart casserole dish with nonstick cooking spray. Set aside.

Step 3

Add the peeled potatoes to a large bowl. Mash them well with a potato masher or a hand mixer. Add the sugar, vanilla, eggs, evaporated milk, and butter and mix very well. Pour the mixture into the baking dish.

Step 4

To make the topping, use a fork to combine the brown sugar, flour, and softened butter in a medium bowl until crumbs form. Add the pecans and stir to combine.

Step 5

Sprinkle about half of the mini marshmallows over the sweet potato mixture, then sprinkle the topping on top. Bake for 30 minutes. Remove from the oven, add the remaining marshmallows over the top, and return to the oven for about 10 minutes or until the marshmallows are golden brown. Allow to rest for about 10 minutes before serving.