Sour Cream Pound Cake Cupcakes With Grapefruit Buttercream Frosting

This idea was inspired by my Lemon-Blueberry Cupcakes. I thought the tartness of grapefruit might be a nice contrast to sweet buttercream. These were pretty good, but I want to experiment a bit more. The icing separated a bit. I think part of the problem was too much grapefruit juice; I only didn't use quite all of the juice out of one piece of fruit. But next time, I think I'll cut it into quarters to squeeze so I can get a more accurate amount. The grapefruit flavor is very subtle. The other issue I had with the icing was that it was a little grainy. I think the butter was too soft. Now that I know what grapefruit tastes like with buttercream, next time I will add orange zest to the cake batter; this will be a nice bridge to the citrus flavor of the icing.

Sour Cream Pound Cake Cupcakes
1/2 cup butter, softened
4 oz. cream cheese, softened
2 cups sugar
4 eggs
1 tsp. vanilla
3 cups all-purpose flour
1 tsp. baking powder
1/2 tsp. baking soda
1/2 tsp. salt
8 oz. sour cream
Vegetable cooking spray
Grapefruit Buttercream Frosting

1. Beat butter and cream cheese with an electric mixer until creamy. Beat in sugar until light and fluffy. Beat in eggs, 1 at a time, beating until blended after each addition. Stir in vanilla.
2. Combine flour and next 3 ingredients. Gradually add to butter mixture, alternately with sour cream, and beat until blended. Pour batter into lightly greased muffin pans.
3. Bake at 350° for 30 minutes or until done. Cool completely before icing. Store in the refrigerator.

Grapefruit Buttercream Frosting
1 cup butter, softened
Juice from 1 grapefruit
1 (16-oz.) box powdered sugar

1. Beat butter until creamy. Gradually beat in grapefruit juice and powdered sugar until mixture is light and fluffy.