In a very large bowl, allow egg whites to stand at room temperature for 30 minutes. Meanwhile, sift cake flour and 3/4 cup of the sugar together 3 times.

Preheat oven to 375 degrees F. Add vanilla and cream of tartar to egg whites; beat with an electric mixer on medium to high speed until soft peaks form (tips curl). Gradually add the remaining 3/4 cup sugar, beating until stiff peaks form (tips stand straight). Sift about one-fourth of the flour mixture over egg white mixture; fold in gently. Repeat sifting and folding in with the remaining flour mixture, using one-fourth of the flour mixture each time. Transfer half of the egg white mixture to another bowl; set both bowls aside.

In a medium bowl, beat egg yolks with an electric mixer on high speed about 5 minutes or until thick and lemon-colored. Fold egg yolk mixture into one portion of the egg white mixture. Alternately spoon dollops of yellow and white batters into an ungreased 10-inch tube pan. Gently cut through the batters with a knife or a narrow metal spatula.

Place tube pan on the lowest oven rack. Bake for 35 to 40 minutes or until cake springs back when lightly touched near center. Immediately invert the cake in the pan, standing the center tube over a tall-neck bottle. Cool thoroughly. Loosen cake from pan; remove cake. Frost with Lemon Fluff. If desired, garnish with raspberries and orange and/or lemon peel strips. Store cake in refrigerator. Makes 16 servings.

Thaw one 12-ounce container frozen light whipped dessert topping. Fold 1 teaspoon finely shredded lemon peel and 2 tablespoons lemon juice into thawed dessert topping. (Add more peel and/or juice for a more intense flavor.)