In a very large bowl, let egg whites stand at room temperature for 30 minutes. Meanwhile, sift flour and powdered sugar together three times; set aside.

Adjust baking rack to the lowest position in oven. Preheat oven to 350 degrees F. Add cream of tartar and vanilla to egg whites. Beat with an electric mixer on medium speed until soft peaks form (tips curl). Gradually add granulated sugar, about 2 tablespoons at a time, beating until stiff peaks form (tips stand straight).

Sift about one-fourth of the flour mixture over beaten egg whites. Sprinkle with finely shredded peel; fold in gently. Repeat, folding in remaining flour mixture by fourths. Spoon into an ungreased 10-inch tube pan. Gently cut through batter to remove any large air pockets.

Bake on the lowest oven rack for 35 to 40 minutes or until top springs back when lightly touched. Immediately invert cake in pan; let stand until completely cool. Loosen side of cake from pan; remove cake.

Meanwhile, for fruit salsa: In a small saucepan, combine orange juice and balsamic vinegar. Bring to boiling; boil gently, uncovered, for 5 to 7 minutes or until reduced to 1/4 cup. Remove from heat; cool completely. In a medium bowl, combine plums and peaches. Add orange juice mixture; toss gently to coat. Cover and chill for up to 24 hours. Stir in snipped mint just before serving.

To serve, slice cake. Spoon fruit salsa over individual servings. If desired, garnish with fresh mint leaves and/or citrus peel strips. Makes 12 (1 slice and 1/4 cup salsa) servings.

Choose Splenda Sugar Blend for Baking. Follow package directions to use product amount equivalent to 2/3 cup sugar. PER SERVING WITH SUBSTITUTE: same as above, except 112 cal., 23 g carbo. Exchanges: 1 other carbo. Carb choices: 1.5