Cook the Sweet Potatoes: Preheat your propane powered oven to 350°F and bake them in the for about 45-50 minutes till soft. Pierce the sweet potatoes with a fork to check of softness. Let them cool for a few minutes. Option to peel or scoop the potato out. Add to a large mixing bowl and mash.
Mix Ingredients: To the mashed sweet potatoes, add the brown sugar, melted butter, eggs, vanilla extract, milk, salt, ground cinnamon, and ground nutmeg. Mix well until all the ingredients are combined.Option to mix crushed pecans into sweet potato mash.
Transfer to Baking Dish: Transfer the sweet potato mixture to a greased 9x9-inch baking dish or a similar-sized casserole dish. Smooth the top with a spatula.
Marshmallow Topping: Sprinkle the marshmallows evenly over the top of the sweet potato mixture.Option to add crushed pecans as topping with marshmallows.
Bake: Place the baking dish in the preheated oven and bake for 25-30 minutes, or until the marshmallows are golden brown and the casserole is heated through.
Serve: Remove the sweet potato casserole from the oven and let it cool for a few minutes before serving. Enjoy your sweet and gooey sweet potato casserole with marshmallows!