#1 Preheat your oven to 375°F #2 Boil the sweet potato cubes until tender. Drain and mash them in a large mixing bowl. Add melted ½ cup of butter, milk, half the brown sugar, beaten eggs, vanilla extract, ground cinnamon, ground nutmeg, and a pinch of salt to the mashed sweet potatoes. Mix until well combined #3 In a separate bowl, combine chopped pecans, the remaining brown sugar, all-purpose flour, and melted butter. Mix until the mixture is crumbly #4 Spread the sweet potato mixture evenly in a baking dish. Sprinkle the pecan topping over the sweet potato layer #5 Bake in the preheated oven for about 25-30 minutes or until the pecan topping is golden brown #6 Remove the casserole from the oven and evenly distribute the mini marshmallows on top #7 Turn on the broiler and place the casserole under the broiler for 1-2 minutes, or until the marshmallows are golden brown. Keep a close eye to prevent burning #8 Allow the sweet potato casserole to cool slightly before serving.