Healthier Chocolate Box Cake - cooking recipe

Ingredients

Cake
5 egg whites
1 1/3 cups 2% buttermilk
1/3 cup unsweetened applesauce
1 (18 1/4 ounce) box chocolate cake mix
Frosting
3 cups confectioners' sugar
2/3 cup cocoa powder
6 tablespoons light butter, at room temp
1/3 cup nonfat milk
1 teaspoon vanilla extract

Preparation

TO MAKE THE CAKE: Preheat the oven to 350^F. Lightly coat a 13\"x9\" baking dish with nonstick spray.
In a large bowl, using an electric mixer set on high speed, beat the egg whites for 1 minute, or until foamy. Beat in the buttermilk and applesauce. Add the cake mix and beat for 2 minutes, or until smooth. Scrape into the prepared pan.
Bake for 30 to 35 minutes, or until a wooden pick inserted in the center comes out clean and the cake is pulling away from the sides of the pan. Cool completely in the pan on a rack.
TO MAKE THE FROSTING: In a small bowl, combine the confectioners' sugar and cocoa, stirring to remove lumps. In a medium bowl, using an electric mixer set on medium speed, beat the butter until fluffy. Gradually beat in the cocoa mixture, milk, and vanilla extract. Beat until very smooth. Spread over the cooled cake, swirling it for a decorative appearance.