This fluffy frosting works so well on angelfood cakes, but is also good on 9x13 cakes. It doesn't require powdered sugar or butter, and uses a comparatively small amount of sugar. Zola Hancock gave me the recipe many years ago as an alternative to buttercream when the price of sugar went up sharply.
Glossy Frosting
3/4 C. granulated sugar
6 Tablespoons light Karo syrup
6 Tablespoons water
scant 1/2 tsp. cream of tarter
For 9x13 cake:
1/2 C. granulated sugar
1/4 C. light Karo syrup
1/4 C. water
1/4 tsp. cream of tarter
For either amount - bring ingredients to a boil and cook til it barely begins to make a thread in cold water. This just takes a few minutes. Meanwhile, beat stiffly 3 egg whites for larger cake or 2 egg whites for smaller cake. Pour syrup over beaten egg whites while beating and beat until cool. Add 1 tsp. desired flavoring (I prefer vanilla, but almond is a good flavor also.) May add food coloring if you want to. Frost cake in fluffy swirls.