Extra sheet trays are good for more than just baking bacon.
One of my favorite everyday treats to make is a simple loaf cake, with an un-iced bundt cake trailing as a close second. Both cakes are casual-snacking gems, and both cakes have a penchant for over-browning in my rental apartment’s oven. It’s not their fault—deep cakes require longer cooking times—but overbrowning can dry out your cake, and I simply won’t stand for it. Preventing overbrowning is easy with an extra sheet pan.
You could be doing everything right and your cake will still turn out overcooked. There are a few reasons why your cookies, cakes, or pies might be browning too fast, or even burning before the interior is finished. Older ovens or lower quality ones can have "hot spots" that throw off your temperature goals; your sheet pans might be made of cheap, thin metal; and it could just be an inherent downside to the item you’re baking. For example, it's not uncommon for loaf cakes to take an hour or more in the oven. The bottom and sides in direct contact with the baking pan are going to cook the fastest and also be the first to brown before the center even gets going.
If you notice your first tray of cookies are overbrowning on the bottoms, or you remember this same cake recipe gave you trouble in the past, put an extra sheet pan under the cake. If you don't normally bake pies and cakes with a sheet pan underneath, start with one and see how it goes before adding a second one.
Doing this adds another layer, albeit thin, between the cake batter and the hot metal grate it’s sitting on. It sounds like no big deal, but it actually makes a big difference. (And isn’t that exactly what a good hack is all about?) If you’re using a second sheet pan that’s a size smaller than the one above it, you’ll notice that it does an even better job at insulating the bottom of the cake because of the air pocket it creates underneath.
The sheet pan protects the bottom. Addressing the sides of the pan is slightly more of a to-do, but still easy. Wrap a layer of aluminum foil around the sides. Shiny aluminum foil reflects energy and adds protection to your food in the oven. I usually do this as a secondary precaution. If my cake has been baking and I notice that it’s nowhere near cooked through the center but the edges are already golden, I’ll loosely wrap some foil around the sides. I do the same thing for pies when the crust looks like it’s taking on lots of color before the filling cooks.
Keep in mind that you’ll likely have to increase the amount of cooking time a bit because the heating will be less aggressive. Unfortunately, I can’t give you a set number for this because it will vary a great deal depending on what you’re making and your oven’s personal problems. This might look like adding two minutes for your cookies, or an extra 15 minutes for a bundt cake. As always, just keep an eye on it, and check for doneness as usual. You’ll get better at assessing what needs an extra sheet pan underneath, and how long to cook it the more you practice.
