Step 1

Preheat oven to 350 degrees F. Coat 16 muffin cups with cooking spray.

Step 2

In a large bowl, combine cake mix, egg whites, water, vanilla, and lemon peel; mix well. Divide mixture equally into muffins cups.

Step 3

Bake 15 to 17 minutes, or until a wooden toothpick comes out clean. Let cool. Using an apple corer or paring knife, cut a hole in center of each cupcake, being sure not to cut all the way through to bottom; remove center.

Step 4

To make the frosting, in another large bowl with an electric mixer on medium speed, beat confectioners' sugar and shortening until creamy, then beat in the heavy cream until smooth and fluffy.

Step 5

Place frosting in a pastry bag or large resealable plastic bag with the corner snipped off. Fill cupcake holes evenly with frosting, then continue to pipe frosting on top of cupcake.