Even if you have a perfectly good oven, there will be times when you can't use it or just plain don't want to. If it's the middle of a heat wave, for instance, and you have a cake to bake for a special occasion, you probably don't want to heat up the kitchen with your main oven. At holidays and family gatherings, your oven might already be tied up with other things. If you own a countertop roaster oven, you can use that to bake a cake whenever your regular oven isn't an option.
Understand the Difference
Although a countertop roaster is described as an oven, it's not exactly the same as a real oven. For one thing, the heat comes entirely from below. You'll have to make sure to bake on the rack that comes with the roaster, so air can circulate underneath. Otherwise, your cake will almost certainly burn on the bottom. A bigger difference is that opening the lid to sneak a peek is a really bad idea, because it lets out so much heat. Heat loss happens when you open the door of a regular oven as well, but because a roaster oven is a smaller space and has a less-powerful heating element, it takes a lot longer to come back up to temperature. The lid is see-through, though, so you shouldn't need to open it until it's time to test the cake.
Choose Your Recipe
Pretty much any cake recipe you already make will fit into the cooking well of a roaster oven, depending on how many pans it takes. A standard 18-quart roaster oven will usually fit a 10- or 12-cup Bundt pan or angel food pan, a 9-inch round or square pan or a 9 by 13-inch rectangular pan. If your recipe makes multiple layers, you might not be able to bake them all at the same time. Some roaster ovens have a second rack that stacks over top of the first one, so you can work around that particular difficulty. Also, some baking cake pans are larger than others, so you might have to try a few to find one that fits properly.
Prepare the Roaster
Once you've settled on your recipe and gotten your ingredients ready, take a moment to prepare the oven. Set the rack in the bottom of the cooking well, and turn on the roaster to preheat. You won't need to make any temperature adjustments, as the temperature you use in an oven is the same temperature you'll use in the roaster. Mix your cake while the oven's heating, and pour the batter into its pan. Use your oven mitts to lift the pan down into the cooking well, because the sides are already at oven temperature and if you do this barehanded, there's a pretty high risk of giving yourself a nasty burn.
Bake Your Cake
Once the cake is in and the lid is on, all you have to do is wait. Start checking the cake through the lid of the roaster as you get closer to the end of the recipe's baking time. Most cakes look fully risen and set for a few minutes before they're actually baked all the way through, so don't let that fool you. Instead, look at the edge of the pan where it meets the cake. When the cake is done, it'll start to pull away from the pan just slightly. When you see that start to happen, that's the time to open the lid and test the cake the traditional way with a toothpick. If it tests as done, lift the cake out – again, protected by oven mitts – and set it on a cooling rack. From that point, it's like any other cake. Let it cool as directed in your recipe before you turn it out onto a wire rack.