Margarita Cake with Key Lime Cream Cheese Frosting

Step 1
Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9×13-inch cake pan.

Step 2
In a large mixing bowl, beat together the cake mix, egg whites, frozen margarita mix, vegetable oil, lime zest, and 1 tablespoon lime juice. Pour the batter into the prepared pan.

Step 3
Bake in the preheated oven until a toothpick inserted into the center shows moist crumbs, 30 to 35 minutes. Cake will be very moist. Cool in the pan.

Step 4
To make frosting, beat the cream cheese and butter together until light and fluffy, and stir in the lemon peel and 1 tablespoon of lime juice. Beat in the confectioners' sugar, 1 cup at a time, scraping the sides of the bowl thoroughly with a spatula after each addition. Spread the frosting over the cooled cake.