To prepare the cupcakes: Allow egg whites and yolks to stand at room temperature for 30 minutes. Line twenty-four 2½-inch muffin cups with paper bake cups; set aside.
Preheat oven to 325°F. Meanwhile, in a large bowl, combine cake flour, sugar, baking powder, and salt. Make a well in the center of the flour mixture.
Add egg yolks, pineapple juice, and oil to flour mixture. Beat with an electric mixer on low speed until combined. Beat on high speed about 5 minutes more or until batter is satin smooth. Thoroughly wash and dry the beaters. In a very large bowl, combine egg whites and cream of tartar; beat with an electric mixer on medium speed until stiff peaks form (tips stand straight). Pour batter in a thin stream over beaten egg whites, folding gently as you pour. Fill muffin cups ⅔ full with batter.
Bake 15 to 18 minutes or until tops spring back when lightly touched. Cool in cups on a wire rack 5 minutes. Remove from cups; cool completely on a wire rack.
To prepare the frosting: Fold together dessert topping and pineapple in a bowl. Spread cupcakes with frosting. Sprinkle with coconut.
Tips: If using sugar substitutes, choose from Splenda® Sugar Blend for Baking or Equal® Sugar Lite. Follow package directions to use product amount equivalent to ¾ cup sugar. Nutrition Per Serving with Substitute: same as below, except 101 cal., 13 g carbo.
To toast coconut, spread in a shallow baking pan lined with parchment paper. Bake in a 350°F oven for 5 to 10 minutes or until golden, shaking pan once or twice, watching closely to avoid burning.