Lemon Cupcakes with Blueberry Frosting

Today is the last day of one of my co-workers.  She is an amazing, talented, and will be missed!  But alas, her fellowship is only so long.  Thankfully she will be staying close.  In true fashion I insisted that she put in a request for a baked good.  She requested lemon cupcakes.  I think these would also be good with raspberry frosting (didn't have any frozen from the summer...only blueberry).

Cupcake:
2 1/4 cups cake flour
1 tablespoon baking powder
1/2 teaspoon salt
1 1/4 cups buttermilk
4 egg whites
1 1/2 cups sugar
Lemon zest from one lemon
Juice from one lemon
1/2 cup unsalted butter, softened
1 teaspoon vanilla
Preheat the oven to 350˚F.  Line the cupcake tin with liners.

In a medium bowl, sift together the flour, baking powder and salt. Set aside. In another medium bowl, whisk together the milk and egg whites until well blended.

Then in another bowl, combine the sugar, lemon zest, and lemon juice. Mix until the sugar is just moistened.  Add the butter and mix until fluffy. 

Taking the egg mixture bowl, add half the flour mixture and mix well.  Then add half of the sugar mixture.  Then add the remaining flour and sugar mixture, alternatively.  Add the vanilla.

Once the batter is smooth, pour into the cupcake tin.  Bake about 18 minutes.

Frosting:
1/4 cup blueberries (thawed if frozen)
1/2 cup  unsalted butter, softened
1 teaspoon vanilla extract
1 tablespoon lemon juice
pinch of salt
3 cups confectioners' sugar

In a food processor, puree the blueberries.  Place in a large bowl and add the butter, vanilla, lemon, and salt.  Mix until well incorporated.  Then slowly add the confectioners' sugar, a cup at a time, until desired thickness is achieved.