Preheat the oven to 350° F. Into a bowl sift together the flour and the baking powder. In another bowl with an electric mixer beat together the eggs and the granulated sugar until the mixture is thick and pale and beat in the flour mixture in batches, beating until the batter is smooth. Pour the batter into a greased 13- by 9-inch baking pan, on it arrange the apples, peeled, cored, and cut into 1/4-inch-thick slices, in one layer, overlapping the slices, and drizzle the butter over them. In a small bowl stir together the brown sugar and the cinnamon, sprinkle the mixture over the apple slices, and bake the cake in the middle of the oven for 45 minutes, or until a tester comes out clean. pc153