I know that there is a pie crust protector available. Is there something comparable to use on a 9x13 cake pan??
If not, are there any suggestions for keeping edge a cake/brownie from being dried out while the middle turns moist???
Try using a magi-cake strip, you can buy them or fashion your own from towels. The idea is that it insulates the sides of the pan so the entire pan heats more evenly.