This is an amazing and easy white cake- perfect for a birthday party cake!
2 ¼ cup flour
1 T baking powder
½ t salt
1 ¼ cups whole milk or buttermilk
4 large egg whites
1 ½ cups sugar
2 t grated lemon zest
1 stick unsalted butter, at room temperature
½ t pure lemon extract
Preheat oven to 350 degrees. Line two round cake pans with wax paper and spray with cooking spray. Sift together the flour, baking powder and salt. Whisk together the milk and egg whites in a medium bowl. Put the sugar and lemon zest in a mixer bowl or another large bowl and rub them together with your fingers until the sugar is moist and fragrant. Add the butter, and working with the paddle or whist attachment, or with a hand mixer, beat at medium sped for a full 3 minutes, until the butter and sugar are very light. Beat in the extract, then add one third of the flour mixture, still beating on medium speed. Beat in half of the milk egg mixture, then beat in half of the remaining dry ingredients until incorporated. Add the rest of the milk and eggs, beating until the batter is well mixed, then add the last of the dry ingredients. Finally mix the batter for 2 minutes to ensure it is well mixed. Divide between the two pans and smooth the tops with a rubber spatula. Bake for 30 to 35 minutes, or until the cakes are well risen and springy to the touch. Cook for 5 minutes, invert on plates and cool completely. Frost with butter cream or 7 minute frosting.