If you end up baking a cake which has a very uneven top, where one side may be much taller than the other. There are several reasons that can cause these results. Here are just a few:
If you are baking more than one pan in the oven, you may not have adequate air circulation. If the side of the pans are touching or too close you can get results like this. When you poured the batter into the pan, you may not have tapped it down or spread it out to make sure that it was evenly distributed across the bottom. These cake mistakes create uneven cakes.
Your oven may be heating unevenly which will produce an uneven cake. You will need to test this by placing pieces of bread across every inch of rack space with your oven set at 300 degrees. After a few minutes start keeping a close eye on the bread. Are any pieces browning faster than others? Once your test is complete (before the bread starts burning) turn off the heat of your oven and open the door to let cool a bit. Using a pair of tongs remove the bread. Your oven or the racks may not be level. While the oven is cool grab a common level to check and see if your oven is truly level.
Picking the right pan for making a cake is also important. If you are baking pies and breads, use a dark pan which will aid in browning the crusts better. When baking cookies or cakes, use a shiny pan. This will help prevent over darkening of the bottoms and sides. And if you decide to use a glass pan, don’t forget to reduce your oven temperature by 25 degrees. You may also want to check for doneness a few minutes before the timer goes off. Make sure you used the right size pan. The uncooked mixture should fill the pan by no more than two-thirds.