The recipe on the Baker's chocolate box says to make these in a 9" x 13" pan, which makes them too thin for my tastes, but I never add nuts, which would add a little volume to the pan. While I understand that some people like nuts in their brownies, I consider that to be a character flaw. I double the recipe and bake in an 11" x 15" pan. If I were making a single batch, I'd use a 9" x 9" pan.