Creating the perfect Sweet Potato Casserole is simple if you follow these steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C).

2. Prepare Sweet Potatoes: Peel and chop the sweet potatoes into chunks. Place them in a large pot, cover with water, and bring to a boil.

3. Cook Sweet Potatoes: Boil the sweet potatoes for about 15-20 minutes or until fork-tender. Drain and let them cool slightly.

4. Mash Sweet Potatoes: In a large mixing bowl, mash the cooked sweet potatoes until smooth.

5. Combine Ingredients: Add granulated sugar, brown sugar, milk, melted butter, eggs, vanilla extract, cinnamon, nutmeg, and salt to the mashed sweet potatoes. Mix until everything is well combined and smooth.

6. Transfer to Baking Dish: Pour the sweet potato mixture into a greased 9×13-inch baking dish, spreading it evenly.

7. Prepare Topping: In a separate bowl, combine chopped nuts, flour, brown sugar, and melted butter. Mix until crumbly.

8. Add Topping: Sprinkle the topping mixture evenly over the sweet potato layer. If desired, add mini marshmallows on top for extra sweetness.

9. Bake: Place the baking dish in the preheated oven and bake for 30-40 minutes, or until the topping is golden brown and the casserole is heated through.

10. Serve: Remove from the oven and let it cool slightly before serving.

Following these steps will ensure that your Sweet Potato Casserole turns out perfectly every time.