Since I do so much baking, I have six 6-inch cake pans and six 8-inch cake pans. But I realize a lot of home bakers don't have so many spare pans. If you only have 2 or 3 pans, you can bake the cake batter in batches. While baking the first batch, let the bowls of colored batter rest at room temperature. When you have a clean pan available, gently scrape the batter into the, trying not to mix it again or disturb it too much, and bake the remaining cake layers. Since baking powder is double acting, you should still get a rise from your cake even though some of the batter wasn't baked immediately.