Occasionally when baking, you may find yourself with a lack of oven space. Smaller than standard ovens pose little problem for most breads and cookies - assuming that they give you the full temperature range of a regular oven - but can pose a challenge for cake-bakers, especially if you want to bake a layer cake. Most standard sized ovens give you enough shelf space that you can fit two cake pans (8″, 9″ or even 10″) on a shelf, ensuring that your cakes bake at the same time, but when the shelf has room for only on pan, you may find yourself with limited options.
One option is to use two racks and switch the cakes halfway through baking. The other is to leave one cake pan sitting on the counter while the other bakes.
The second option, in this instance, is less preferable. Chemical leaveners are typically used in cakes. Baking soda reacts with moisture, meaning that some of its potency would be lost before the cake has time to “set” in the oven. Baking powder is double acting, so it reacts with both moisture and heat. A baking powder cake will fare better than a baking soda-only cake, but it is likely that it, too, will not rise quite as high as the cake that made it to the oven without a wait period. I should note that if you are baking a three layer cake, this might be your only option. Fortunately, those layers are often thinner than “regular” cake and, when the wait is only 20 or 30 minutes, it will still rise well, just a bit less than if there were no wait time.
The better solution is to use two racks. Switching the cakes ensures that each pan will get even exposure to the oven’s heating elements, so you will end up with evenly baked and well-risen cake layers. In spite of the various old wives’ tales that float around, the vast majority of cakes will be able to handle switching from one rack to another without collapsing.