Roaster ovens are a versatile kitchen appliance and can be used for baking, roasting and even slow cooking. While they typically don't get as hot as a traditional oven, they can still be used to bake cakes and cookies. When baking in a roaster oven, it's important to use the correct bakeware. Roaster ovens have a tendency to heat up quickly and unevenly, so dark-colored or non-stick pans are best. Be sure to preheat your roaster oven before getting started on your cake or cookies. The general rule of thumb is to set the temperature 25 degrees lower than what the recipe calls for when using a traditional oven.