Brush butter and flour mixture over the inside of 2 cake pans, 10 inches (25 cm) in diameter, or coat with pan spray. Reserve.
Place the eggs, granulated sugar, cake flour, and baking powder in a mixer bowl. Stir at low speed, using the whip attachment, until the mixture forms a paste. Add the shortening and whip at high speed for 2 minutes, scraping down the s