Directions

1. Preheat oven to 325 degress, with rack in lower third of the oven. Sift together flour and 3/4 cup sugar. Repeat sifting four times.
2. Beat egg whites and the warm water with a mixer on low speed until foamy. Add salt, cream or tartar, and vanilla, and beat on medium speed until soft peaks form, about 3 minutes. With mixer running, gradually add remaining 3/4 cup sugar, 1 tablespoon at a time. Raise speed to high, and beat until peaks are stiff and glossy (but not dry), about 2 minutes more.

   

3. Transfer mixture to a large bowl. Sift flour mixture over egg-white mixture in six parts, gently folding in each addition with a rubber spatula.
4. Gently pour batter into a 10-inch tube pan. Run a knife through the batter to release any air bubbles, and smooth with an offset spatula. Bake until cake is golden brown and springs back when touched, 40 to 45 minutes.
5. Invert pan on a wire rack, and let cake cool about 1 hour. Carefully run a paring knife around side of cake to loosen, then unmold onto the wire rack.
6. Arrange cotton candy in a ring shape on a serving platter. Lay cake on top of cotton candy "cloud." Serve with caramel whipped cream, if desired.