1. Preheat oven to 350 degrees and line pans with cupcake liners.

2. Sift cake mix into a small bowl to remove any lumps.

3. In a large bowl, gently whisk egg whites, oil, buttermilk, lemon juice, sour cream, vanilla and lemon zest together.

4. Combine cake mix and wet ingredients and stir well.

5. Fill cupcake liners 3/4 full and bake for 15-20 minutes, or until and inserted knife comes out clean.

6. Lemon Glaze: In a bowl, combine all ingredients using a whisk. Add powdered sugar until your glaze reaches the consistency of tomato soup. (I can't think of anything else that has that consistency...)

7. Use a toothpick to punch small holes into the top of each cupcake so the glaze can sink into the cake.

8. Spoon glaze over the nearly cooled cupcakes, and allow time for the glaze to set.

9. Cream Cheese Frosting: Beat butter and cream cheese for 2 minutes. Scrape down bowl and continue to beat in vanilla extract and powdered sugar. Slowly add powdered sugar until you reach your desired consistency. If frosting becomes too thick, add 1 tablespoon of milk.

10. Pipe frosting into cooled cupcakes and top with lemon slices or sprinkles.