In a bowl, combine flour, sugar and baking powder. In another bowl, lightly beat egg yolks. Add milk, butter and vanilla; mix well. Stir into dry ingredients just until combined. Beat egg whites until stiff peaks form; fold into batter.
Bake in a preheated waffle iron according to manufacturer's directions until golden brown. Serve with strawberries or syrup. Yield: 10 waffles (about 4-1/2 inches).