Pastries sometimes brown too much on the bottom before cooking through. This is because the oven is usually hotter on the bottom, near the heat source. To avoid this, preheat the oven 250°F hotter than the baking temperature called for and turn it down to the correct baking temperature once you start baking. Don’t open the oven door any sooner than you need to. In this way, the oven doesn’t ignite as soon so less heat comes up from the bottom. On the other hand, when baking a soufflé, it helps to have heat coming from the bottom so the body of the soufflé heats faster than the top. If the top cooks first, the crust can keep the soufflé from rising. For soufflés, preheat the oven 25°F lower than the eventual baking temperature and turn the heat up as soon as you put the soufflés in the oven.