-
Preheat oven to 350 degrees and line two 12-cup muffin tins with cupcake liners.
-
With a mixer, cream butter until light and fluffy, about 1-2 minutes. Add in granulated sugar and cream until well combined, about 1 minute. Add in eggs, one at a time, beating well after each addition.
-
In a separate bowl, sift flour, corn starch, baking powder, baking soda, and salt together.
-
Alternately, add dry ingredients and buttermilk to the butter mixture, beginning and ending with dry ingredients, stirring until just combined.
-
Add in vanilla extract and sour cream and mix until combined.
-
Divide batter evenly between cupcake liners, filling each about 2/3 of the way full.
-
Bake for 20-22 minutes, or until a toothpick comes out clean. Allow to cool.