1 stick unsalted butter (1 stick) at room temperature
3/4 cup sugar
2 whole eggs, separated, at room temperature
1 1/2 cup flour
1 1/2 teaspoons baking powder
1/4 teaspoon baking soda
1/4 teaspoon salt
1/4 cup pink grapefruit juice
1/4 cup cranberry juice
1 whole small grapefruit, zested
3/4 cup chopped cranberries *see Note
Preheat the oven to 350°F. Line cupcake pans with liners.
With an electric mixer on medium speed cream together the butter and sugar until fluffy, 3-5 minutes. Add the egg yolks. Beat well.
In a separate bowl combine the flour, baking powder, baking soda, and salt.
Add the dry ingredients to the creamed mixture alternately with grapefruit juice and cranberry juice. Fold in the grapefruit zest and chopped cranberries.
With a clean electric mixer beat the egg whites until stiff. Gently fold the whites with a spatula into the batter.
Fill the cupcake liners one-half to two-thirds full. Bake for about 18 minutes or until a toothpick inserted in the center of cupcake comes out clean. Cool cupcakes in the pan for 5 minutes the move to racks to cool. Makes 15 cupcakes.
Recipe from here.
*NOTE- I couldn’t find fresh or frozen cranberries, so I took dried cranberries and chopped them up and used cranberry juice to reconstitute them!
In a large bowl cream together the powdered sugar and butter on medium speed until smooth(*see Note). Mix in lime zest, lime juice, and food coloring until desired spreading consistency is achieved.