Few things satisfy an early morning appetite better than a hearty breakfast casserole. Whether it's a sausage, egg and cheese strata or a sweet, gooey French toast-style creation, reheating a breakfast casserole is an easy way to enjoy that tasty treat for more than just one meal. However, it's important to ensure the breakfast casserole is stored properly and reheated to a safe temperature.
Reheating the Traditional Way
Transfer any leftover breakfast casserole to a clean, oven-proof dish. Cover it with a lid or foil immediately after you've finished eating and place it in the refrigerator. When it's time to reheat, allow the dish to come to room temperature before putting it into a hot oven. Preheat the oven to 350 degrees Fahrenheit. Cover a leftover egg-, potato- or meat-based breakfast casserole with a piece of foil so the moisture will not escape and to ensure even heating. Alternatively, if you are reheating a French toast casserole, bake it uncovered to prevent it from becoming soggy. Bake the leftover breakfast casserole for about 30 minutes or until an embedded food thermometer reaches 165 F. If you want to crisp your casserole, broil it for about 2 minutes after it has been sufficiently heated.
Microwave and Stovetop
To reheat your breakfast casserole in the microwave, ensure the food is distributed evenly in the dish or on the plate. Cover it with plastic wrap and leave one end open to allow the steam to escape. Reheat the casserole in short bursts -- about 3 minutes on "High" at first. Insert a food thermometer in several places of the casserole, as microwave cooking often leaves cold spots in the food. Stir, if desired, and continue with the "short burst" method until the breakfast casserole reaches 165 F. You can also reheat the breakfast casserole on the stovetop. Spray a nonstick pan or iron skillet with cooking spray or melt about 1 tablespoon of butter over medium heat. Place the breakfast casserole into the pan and lay a piece of foil over the top. Heat the casserole to 165 F. These methods may not produce the same texture as the oven, but they will suffice if you are in a hurry.