Grate the yellow outside rind of 1 orange into a bowl. Add 1-1/2 cups sugar and 3/4 cups butter and beat to a cream. Then add yolks of 3 eggs. Then stir in 1 cup milk, 2-1/2 cups flour with 2 heaping teaspoonfuls baking powder. Lastly, add the stiffly beaten whites of 3 eggs. Bake in three layers.