1. Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius).
2. Peel the sweet potatoes and cut into large chunks. Put into a pot and cover with water. Bring to a boil, then lower flame to a simmer. Cook until soft, about 25 to 30 minutes.
3. Mash the potatoes and add remaining ingredients. Bake in a nine-inch (23-centimeter) round pan for 45 to 50 minutes.