When adding the flour, eggs and other ingredients to the mixture, do not overwork it or you may destroy the air bubbles and the lightening effect of the creaming.Serves 12IngredientsFor the cake:3 1/4 cups cake flour1 Tbs. baking powder3/4 tsp. salt1 3/4 cups milk1 Tbs. vanilla extract16 Tbs. (2 sticks) unsalted butter2 cups sugar1 Tbs. finely chopped lime zest4 eggsFor the frosting:4 egg whites1