Preheat the oven to 325 degrees.

Peel and cut sweet potatoes into 1 inch cubes. Add to a large saucepan, cover with water, and cook for 12-15 minutes over medium/high heat.

Once the potatoes are tender, drain the water, then mash them.

Add the mashed sweet potatoes to a large bowl, then mix in the eggs one at a time.

Next, mix in the sugar, milk, butter, and vanilla until you’ve reached a smooth consistency.

Pour the mixture into a 9x13-inch casserole dish.

Combine the brown sugar and flour in a small bowl, then cut in the butter with a fork until you have small clumps.

Sprinkle the topping evenly over the sweet potato mixture, then transfer to the oven and bake for 30 minutes.

Remove from the oven and turn it onto broil.

Sprinkle marshmallows over the top of the sweet potato casserole in a single layer. Return to the oven to broil for 1-2 minutes until the marshmallows are slightly toasted. NOTE: You will need to watch closely so they do not burn.

Remove from the oven and allot to set for 5 minutes, then serve.