1. Preheat oven to 350°. Place 12 muffin cup liners in muffin tin.
2. Place flours in a bowl. Sift sugar, baking soda, and salt into bowl.
3. Whisk butter and oil in a bowl. Add buttermilk and next 4 ingredients (through vanilla), whisking until well-combined. Add dry ingredients to wet.
4. Divide batter evenly among liners, and bake in middle of oven about 25 minutes or until wooden pick inserted in center comes out clean. Cool 5 minutes; transfer to a wire rack to cool.
5. Pipe frosting on cakes with a star-tipped pastry bag.
Skinny it up! Skip the frosting for a 216-calorie treat.