Problem Solving Angel Food Cake

Buzz granulated sugar in a food processor until powdery.

Why? Store-bought granulated or confectioners' sugar can clump and result in a heavy cake. We process granulated sugar into homemade superfine sugar; the resulting sugar is powdery and fine and makes a lighter cake. If you have boxed superfine sugar, you can substitute 12 1/4 ounces of it for the granulated sugar and skip the processing step.

Add the flour mixture to the sugar in the processor and process until aerated, about a minute.

Why? Processing the flour removes lumps and lightens its texture so it won't crush the fragile whipped egg whites.

Gradually add the reserved processed sugar and whip until soft, glossy peaks form. Add vanilla and mix until incorporated.

Why? Adding the sugar slowly helps prevent the whites from deflating.

Sift one-third of the flour mixture onto the whites at a time, gently folding with a rubber spatula after each addition.

Why? Sifting further lightens the aerated flour, helping to prevent the whites from deflating.

Do not grease the pan. Pour the batter right in.

Why? This cake rises only slightly in the oven, but it won't rise at all if the batter can't "grip" the sides of the pan.

Carefully invert the hot cake to cool in the pan; pans without feet can be placed inverted on the neck of a bottle.

Why? Cooled right side up, angel food cakes can be crushed by their own weight.

When the cake has cooled, run a knife (a plastic knife is fine) around the inside edge to loosen it. Turn out the cake onto a platter.

Why? The knife is necessary because the pan isn't greased. A plastic knife won't scratch the nonstick tube pan.