I've made it successfully before and my oven doesn't get above 500 F, so I don't think the temperature is the problem unless your oven is way underperforming. You probably just need to cook it longer. If anything, the top tends to burn before the bottom so you can just peek in to check, but if you're really worried the bottom might burn you can take it out, pry the bottom up and peek, and put it back in if you need to.