01 -
Peel the sweet potatoes and cut them into large chunks. Place them in a large saucepan and cover with water.
02 -
Bring the water to a boil and cook the sweet potatoes until they are tender and easily pierced with a fork. They should be soft enough to fall apart easily.
03 -
Drain the sweet potatoes and return them to the saucepan. Use a potato masher to mash them thoroughly.
04 -
Add the rest of the filling ingredients: butter, brown sugar, salt, cinnamon, vanilla extract, and nutmeg. Mix everything together until well combined.
05 -
Grease a 9x13-inch baking dish with cooking spray.
06 -
Spread the sweet potato filling evenly in the prepared baking dish. Top with mini marshmallows, spreading them out in an even layer.
07 -
Bake the casserole in a preheated oven at 350 degrees Fahrenheit for 25-35 minutes, or until it is bubbly and the marshmallows are golden brown on top. Watch closely towards the end to achieve the perfect golden brown color without burning.