Wash & scrub the sweet potatoes thoroughly, then place them on a cookie sheet, and bake them on 350 F for about 35 minutes, or until tender.
Once the sweet potatoes are done, scoop out the filling & place the filling into a large mixing bowl.
Next add in the melted butter, 1/2 cup granulated sugar, maple syrup, milk, vanilla extract, ground cinnamon, ground nutmeg, and ground clove.
Mix all the ingredients, then add in 3 large eggs.
Mix everything until well incorporated then set to the side.
Toss all the ingredients into a large bowl, and mix with a fork, until it's nice and crumbly.
Build the casserole
Butter up a 9x13 bake dish, then pour in the sweet potato filling.
Toss the marshmallows on top of the sweet potato filling.
Next, sprinkle the crumbly topping on top of the casserole.
Leave the casserole uncovered, and bake in the oven on 350 F, for 45 minutes.
Once done let the casserole sit for 10 minutes.
Serve & enjoy!