Lemonade Layer Cake Ingredients Cake: 1 1/3 cups granulated sugar 6 tablespoons butter, softened 1 tablespoon grated lemon rind 3 tablespoons thawed lemonade concentrate 2 teaspoons vanilla extract 2 large eggs 2 large egg whites 2 cups all-purpose flour 1 teaspoon baking powder 1/2 teaspoon salt 1/2 teaspoon baking soda 1 1/4 cups fat-free buttermilk