baking time question
I'm baking a carrot cake. Instead of baking it in two 8" rounds for 45-50 minutes, I'm using a 9x13. How should I adjust the time?
Assuming that the cake layers bake for 25-30 minutes (if your recipe states 45-50 minutes for 8" layers, I think that's way too long for baking time, but I haven't seen your recipe) in the 8" rounds, you'd probably need another 10 minutes, for a the total of 35-40 minutes in a 9" x 13"; if it's a glass pan, the heat needs to be decreased by 25°.
However, I never rely totally on a timer; rather I check cakes for doneness, cake tester, toothpick, broom straw, whatever; and use an oven thermometer. Set the timer for 30 minutes initially, and check the cake periodically until done.