Ingredients
▢5 pounds sweet potatoes
▢4 tablespoons butter
▢2 eggs slightly beaten
▢1 teaspoon salt
▢1 teaspoon ground cinnamon
▢1/2 teaspoon vanilla extract
▢1/2 teaspoon ground nutmeg
▢1/2 cup dark brown sugar
▢1/4 cup heavy cream
▢Butter for greasing baking dish
Crumble Topping + Marshmallows
▢1/2 cup all-purpose flour
▢1 cup dark brown sugar
▢1/4 teaspoon salt
▢1 cup quick-cooking oats
▢1/2 teaspoon ground cinnamon
▢1 stick butter cut into chunks
▢2 cups miniature marshmallows
Instructions
Sweet Potato Layer
Preheat the oven to 350 degrees F.
Wrap sweet potatoes in foil, place them on a baking sheet and bake for about 1 hour or until fork-tender. *If using canned sweet potatoes, skip this step (be sure to drain syrup).
Once potatoes are cool enough to handle, remove and discard skins and any tough, stringy pieces. Place the cooked potatoes into a large bowl. Mash the sweet potatoes together with the butter using a potato masher until mostly smooth.
Add the eggs, salt, cinnamon, vanilla, and nutmeg and continue to mash until you have a uniform mixture. Add the brown sugar and cream and mix well.
Cookie Crumble
Combine the flour, brown sugar, salt, oats, and cinnamon in a medium bowl and stir together well. Stir in the chunks of butter, using a fork to mix until you have streusel-like crumb.
Assemble and Bake
Lightly coat a 9 x 13-inch baking pan with butter or non-stick spray. Spread the sweet potatoes in the pan. Top with the marshmallows first, then crumble the oatmeal crust on top of the marshmallows. Bake 30 to 40 minutes at 350 degrees.