1teaspoonfresh lemon zestjust the yellow part not the pith
½teaspoonpure vanilla extract
3+ ½ cups confectioners' sugarsifted
Instructions
Make the cupcakes:
Preheat oven to 375 degrees F. Line a 12-cup muffin pan with baking cups.
Sift together flour, baking soda, baking powder and salt.
Beat the butter and sugar together on high speed until pale and fluffy about 3 minutes. Beat in eggs 1 at a time then vanilla.
Scrape down sides of the bowl. On low speed beat in flour in 3 additions alternating with sour cream starting and ending with flour. Fold in blueberries.
Fill baking cups ⅔ full.
Bake about 20 minutes until toothpick comes out clean with a few moist crumbs - not raw batter - attached. Cool completely on wire racks before frosting.
Make the frosting:
On medium speed beat the butter and cream cheese together until fluffy, 2 to 3 minutes. On low speed beat in vanilla, lemon zest and confectioners' sugar. Turn up to medium speed and beat until light and fluffy 4 - 5 minutes. Refrigerate frosting 20 minutes.
Frost cupcakes. Store in refrigerator and bring to room temperature before eating.