An angel food cake pan is a flat bottomed tube pan with or without a removable bottom. The sides and central tube supports the light batter as it rises during baking. Do not grease or flour angel cake pans; a clean dry, grease free pan is essntial for the cake to rise properly. Scrub your pan with detergent before use, if not perfectly clean. When the cake is baked, the pan must be turned upside down and allowed to cool for at least 1½ hours to prevent it sinking.