3tablespoonsvegetable oilor melted and cooled butter
Optional Streusel
1/4cupall-purpose flour
1/4cupbrown sugar
2 to 3tablespoonsmelted butter
Instructions
Preheat oven to 400°F and grease a 12-cup muffin tin or line with paper liners.
In a large bowl sift together flour, baking powder, baking soda, salt, and cinnamon.
In another bowl, beat together the sweet potato and brown sugar, then beat in the egg and vanilla. Stir in milk and vegetable oil. Stir dry ingredients into the sweet potato mixture until combined, but do not overmix.
Optional streusel: Mix together 1/4 cup flour and 1/4 cup brown sugar, then use a fork to mix in 2 to 3 tablespoons of melted butter until clumps form. Sprinkle over the tops of the muffin batter.
Bake for 15-18 minutes, or until a toothpick inserted in the center comes out clean.