Kahlúa and Cream Cupcakes

Why I Love This Recipe
The cupcake recipe comes from Crazy About Cupcakes by Krystina Castella. The frosting recipe was created by me!
Ingredients You'll Need
12 tablespoons (1 1/2 sticks) unsalted butter, at room temperature
1/2 cup cocoa powder
1 1/2 cups granulated sugar
1 tablespoon vanilla extract
3 large eggs, separated, at room temperature
1/2 cup cold water
1/2 cup Kahlúa
2 1/4 cups all-purpose flour
3 teaspoons baking soda
1/2 teaspoon salt
Directions
Preheat the oven to 350°F. Insert 24 liners into a medium cupcake pan.
In a large bowl cream together the butter, cocoa, sugar, and vanilla with an electric mixer on medium speed until light and creamy, 3-5 minutes. Add egg yolks and beat for 4 minutes.
In a small bowl mix water and Kahlúa.
In another large bowl combine the flour, baking soda, and salt.
Add the dry ingredients to the creamed mixture alternating with the Kahlua mixture. Mix on medium speed until ingredients are completely combined.
With clean beaters and a large bowl, beat the egg whites on high speed until they form soft peaks. Gradually beat in the remaining sugar to make a meringue (see MY NOTES above). With a rubber spatula, fold the meringue into the batter.
Fill the cupcake liners 3/4 full. Bake for 20-25 minutes or until a toothpick inserted in the center of cupcake comes out clean. Cool cupcakes in the pan.