- Preheat oven to 350 °F.
- Separate 7 eggs.
- Beat whites until stiff but not dry.
- Add two whole eggs to the yolks and start beating.
- Gradually add sugar, lemon juice and rind while continuing to beat.
- Add potato starch and matzo cake flour.
- Carefully but thoroughly fold in beaten whites.
- Bake in an ungreased 10-inch tube pan for 40–50 minutes.
- Invert pan until cool.