How Do You Reheat a Casserole in the Oven?

The directions for reheating a casserole in the oven vary depending on whether the casserole is frozen; however, the general rule for a frozen casserole is to cook at 350 degrees Fahrenheit for approximately 45 minutes, and then for up to 30 minutes at 325 F. To prevent foodborne illnesses, casseroles should be cooked until they reach 165 F.

When reheating a casserole that has not been frozen, follow the original instructions set forth in the dish’s recipe, but add about 10 minutes to the total to make sure that the dish reaches the necessary temperature. Always cover a reheated casserole with aluminum foil.