Pair with cream cheese frosting (my favorite!) or a more pipeable buttercream frosting.
Once incorporated, add in the vanilla, water, sour cream, and egg whites one at a time until combined.
Place cupcake liners into cupcake tin and scoop 3 tablespoons of batter into each baking cup.
Adapted from: Recipe Girl
To turn this into a 9x13 cake, bake at 350 for about 30 minutes or until toothpick comes out clean.
Buttercream Frosting recipe can be found here.