In a small bowl, combine flour and baking powder.
In a large bowl, combine egg whites, 1/4 cup of sugar and whip with an electric mixer until stiff but moist peaks form.
In a separate large bowl, combine egg yolks, vanilla and remaining 1/4 cup sugar then whip until creamy and light in color, about 4-5 minutes. Fold egg whites into the yolk mixture gently but thoroughly. Next, fold in flour.