Creating Southern Sweet Potato Casserole is straightforward if you follow these simple steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C).
2. Prepare Sweet Potatoes: Boil the sweet potatoes in a large pot of water until tender. Once cooked, drain, peel, and mash them in a large mixing bowl.
3. Mix Ingredients: Add granulated sugar, melted butter, milk, eggs, vanilla extract, cinnamon, nutmeg, and salt to the mashed sweet potatoes. Mix until smooth and well combined.
4. Transfer to Baking Dish: Pour the sweet potato mixture into a greased 9×13 inch baking dish, spreading it evenly.
5. Prepare Topping: In a separate bowl, mix together the brown sugar, flour, and softened butter until crumbly. If you’re using pecans, fold them into this mixture. Alternatively, leave them out for marshmallow topping.
6. Add Topping: Spread the topping evenly over the sweet potato mixture. If using marshmallows, layer them on top instead.
7. Bake: Place the casserole in the oven and bake for 30-40 minutes. Look for a golden brown topping and bubbly edges.
8. Cool Slightly: Once done, remove it from the oven and let it cool for a few minutes before serving for best texture and flavor.

These steps will guide you through creating a rich and delicious Southern Sweet Potato Casserole that everyone will love.