1. Position oven rack in lower third of oven. Heat oven to 375 degrees F.
2. Mix 3 tablespoons flour and 3 tablespoons sugar in medium-size bowl. Sift remaining flour, 3/4 cup sugar and salt, twice, onto waxed paper.
3. Beat whites and juice in large bowl at medium speed until soft peaks form.
4. Gradually beat in remaining sugar until glossy peaks form. Beat in vanilla.
5. Add yolks and rind to flour mixture in medium-size bowl. Beat at high speed until pale yellow and ribbon forms when beater is lifted, 3 minutes.
6. Fold sifted flour mixture into egg whites in 3 additions. Remove a third of whites mixture; fold into yolk mixture.
7. Alternately spoon yellow and white batters into ungreased 10-inch tube pan. Run thin, long knife through batter, swirling batters together.
8. Bake in 375 degree F oven 35 to 40 minutes, until golden and wooden pick inserted in top tests clean. Invert pan onto bottle to cool. Run thin knife around edges; remove cake from pan. Makes 16 servings.