I cannot for the life of me get my banana bread to bake evenly. I have tried different loaf pans. I think I have not gone throug 4 or 5 of them now. Each as the same result. It seems that the bread is always darker around the bottom half then on the top. For some reason, I can't get it to cook evenly throughout the entire loaf. I'm cooking it at 350 degrees, for over an hour. The oven seems to be at the right temperature. So not sure what else do to? Anybody have any suggestions?