Hi - I am headed to camping trip with a shared potluck dinner the first night. I want to bake a fruit crisp in a 12x20 steam table type of pan. Fruit will start from frozen and is mixed peaches and berries. How should I bake this so that the fruit cooks through without burning the crumbs on top? I'm inclined to more time, lower temp and raise the temp at the end if the crumbs aren't browned. Or partially cook the fruit covered, then uncover and add the crumbs halfway through. Any help would be appreciated.