Preheat the oven to 350 degrees F (175 degrees C).
Place the cubed sweet potatoes in a large baking dish.
In a small bowl, combine the melted butter, brown sugar, cinnamon, nutmeg, and vanilla extract. Pour the mixture over the sweet potatoes and stir to combine.
Bake in the preheated oven for 40 minutes, stirring every 15 minutes.
Sprinkle with chopped walnuts if desired and serve.
Interesting Facts
Sweet potatoes are a good source of dietary fiber, vitamin A, and potassium.
This casserole can be served as a side dish at any meal or as a dessert.
It is also a great option for a vegan or egg-free diet.