1. Preheat the oven to 400 degrees. Line a twelve-cup muffin tin with paper liners or coat with nonstick spray. In the bowl of a stand mixer fitted with a paddle attachment, beat butter and sugars on medium-low speed until light and fluffy. Add eggs, one at a time, beating well after each addition. Add remaining ingredients and beat on low speed until well-mixed. Spoon batter into prepared muffin tin.
2. Bake until a toothpick inserted into the center of a muffin comes out clean, 18 to 20 minutes. Serve immediately.
If you have leftover sweet potatoes at home, apart from muffins, you can try to make sweet potato candy to finish your stock.