Not that pans are able to actually relate to each other, but do you ever wonder how to reduce or enlarge your baking pan size when you reduce or increase the recipe? Well, I have. And, this is something to have figured out well before a big holiday like Christmas.
Sometimes I just don’t need an entire 10 cup size Bundt Cake recipe for a holiday meal. Do I cut the recipe in half and use a standard 6 cup Bundt pan? If I need a 9”x13” cake pan size, but the recipe I want to use is for an 8”x8” pan, do I double the recipe? Well, not really. The replacement pan will not exactly fulfill your expectations. Normally I use my high school math to figure out the proper proportions (you know – using that pi-r-square formula), but one time I was a little off and it showed badly in the finished cake. The cake ended up too thin. ARRRGGGHHH!
I don’t have all sizes of all shapes of baking pans and don’t plan to invest in all of them…so, here’s an easy way to relate to your pans and reform a recipe for a different sized pan. What I do is double or half my recipes and err on the side of going with the larger amount of batter. If it’s too much batter for the new pan, I just fill it as I normally would and put the extra in a small ceramic dish and bake them both. Then I have a pan to take to the party and a little to keep at home. What a deal!
Round Pans and Approximate Total Area:
8” 50 square inches
9” 64 square inches
10” 79 square inches
Square and Rectangle Pans and Approximate Total Area:
8” 64 square inches
9” 81 square inches
9”x13” 117 square inches
So, according to the approximate total area, a 9” round baking pan equals an 8” square pan, so you can interchange those pans pretty easily.
But, when you come to increasing a recipe from a smaller pan to a 9”x13” pan, it’s better to err on the larger size recipe. So, if you double your recipe for a 9” round pan, you’ll get to 112 square inches for the area, which is just under the total approximate area of the 9”x13” pan. That is pretty close. It should be pretty easy to make the doubled recipe for the 9” round pan to work for the 9”x13” pan.
But if you decide to double a 9” square pan recipe to fit in a 9”x13” pan for a party, 2 times 81 square inches equals 162 approximate total area. That’s going to give you quite a bit more batter than the 117” approximate total area of the 9”x13” rectangle pan. I usually go ahead and make the double recipe and pour much of the batter in the larger pan and pour the rest of the batter in an 8” round pan. That’s because 162 minus 117 equals 55 which is pretty close to what the total approximate area is for an 8” round pan. That way you get a 9”x13” pan for the party and an 8” round pan for your family. What a treat! I always go with the larger amount of batter, fill the pan I need for the party so it’s not lacking in size or thickness, and have a smaller version for the family.
Regarding baking time and temperature. You'll probably want to bake the cake at the original temp - usually around 350F degrees. But, you may want to lengthen or shorten the time to bake. Err on the shorter time period to bake the cake and give it the finger tap test or the the clean toothpick test. If you open the oven and lightly tap the top of the cake and it bounces back into place it's probably done. If it leaves a dimple in the cake top, it probably is not done. To test it further, stick a toothpick in the center and if it comes out clean, the cake is done. If the toothpick pulls out some batter along the pick, it's probably not done. Bake a little longer, in 5 minute increments and retest.
If this is too confusing or convoluted for anyone, go ahead and invest your hard earned money in all those pans to overfill your cupboards and don’t ever use your high school math skills to make adjustments to your recipes. Or, order a tasteless run of the mill cake from the local big box bakery. But, that’s downright boring. Live a little and take a chance. It’s just a cake. It’s not the end of the world.
Whatever you do, "Bake your own Memories!" and have fun!