Preheat the oven to 375º F.
Line muffin pan with cupcake liners of your choice. We chose green.
Cream together the butter and sugar until fluffy.
Add in the egg whites. Beat well
Put in the sour cream and vanilla extract then fold into the butter and sugar mixture.
In a medium bowl, combine the flour, baking powder and salt and gently mix to incorporate.
Add half of the flour mixture into the wet ingredients. Mix well
Add the other half of the flour mixture and mix until you cannot see any dry flour.
Add green food coloring to the color you desire.
Fill your cupcake liners about 1/2 to 2/3 full.
Bake at 375º F for 5 minutes, then reduce heat to 350º. Keep the cupcakes in the oven for another 8-10 minutes.
Remove from oven.
Let cupcakes cool.
Beat the butter and shortening with an electric mixer until smooth.
Add in 2 cups of powdered sugar and beat until you do not see any clumps of sugar.
Add in more powdered sugar, mixing frequently until there are no more lumps and it is a thick consistency.
Add the watermelon Kool-Aid powder and a small amount of red food coloring (until you reach the color you desire) and mix well.
Spoon the frostingHow to assemble down into a large piping bag with a tip. We used a 1m piping tip.
Start in the center of the cupcake and swirl out to the sides and then back in to the center of the cupcake, stacking the frosting as you go
Sprinkle some mini chocolate chips on top of the frosting.
Makes 10-12 cupcakes.