How to Defrost and Reheat a Casserole the Right Way

Secrets of the thaw, right this way.

Creamy Kale and Pasta Bake
Photo: Hector Manuel Sanchez

Everyone has their own style when it comes to casseroles—preparing them, baking them, serving them, storing them, thawing them—and we wouldn't dare tell Aunt Joan that she's doing it wrong. We do have a few tips, though, for those moments when you have a frozen casserole waiting and are unsure how to proceed. How do you get that currently-iced-but-potentially-warm-and-delicious casserole from freezer to table? There are rules, depending on whether that casserole is store-bought or homemade. The laws of thaw are as follows.

Defrosting Is Key

Taking the casserole from the freezer and putting it straight into the oven is not a good idea. You'll probably end up with overdone edges and a chilly middle. There is a caveat to this, though. If it's a frozen, store-bought casserole, you should follow the instructions on the package. Many of these store-bought numbers recommend putting the casserole into the preheated oven straight from the freezer, no thawing involved. If there are instructions, they should be your guide.

If you're working with a homemade casserole, though, most Southern cooks will tell you that defrosting is an essential step. Thawing the casserole first can help to ensure even baking—no icy centers allowed. The biggest mistake in this process is not giving yourself enough time. It's not advisable to attempt to thaw your casserole in the oven or in the microwave. Instead, you should place your frozen casserole in the refrigerator and let it thaw overnight. The refrigerator's cool temperature will allow for a mild thawing process and, in turn, will help your casserole bake evenly.

Reheating a Casserole

After the casserole has defrosted, it's then time to place it in the oven for the reheating step. Keep in mind you may need to add a few minutes to cooking time. Let the casserole stand at room temperature while the oven preheats.

If your casserole isn't pre-baked, follow any final steps to complete the recipe, such as adding a breadcrumb topping or shredded cheese, then resume the recipe's directions for baking.

If you baked your casserole ahead of time, simply cover the dish with foil and reheat at 350˚F until heated through. Depending on the type of dish, you may need to add moisture to keep it from drying out, for example, a splash of milk to baked macaroni and cheese.

Testing Doneness

Check the center of the casserole with a thermometer to ensure it has reached the appropriate temperature, and you'll be on your way to dinner with a beautifully defrosted and reheated casserole. (Check out some of our favorite make-ahead casseroles for your mealtime inspiration this week.)

Freezing Tips

One of the great things about casseroles is that you can make two, one to serve for dinner now and one to freeze for later. Once you are spoiled by the convenience of reheating a frozen casserole during a busy week, you'll want as many dishes as possible in your repertoire. The good news is that most casseroles can be frozen, from lasagna to macaroni and cheese to chicken and rice. If your casserole contains ingredients that don't freeze well, like mashed potatoes, then it may not be a good candidate.

If your casserole has raw protein, like chicken or shrimp, make sure to bake it and cool it completely before freezing. If it doesn't have protein or the protein is cooked, no pre-baking is necessary. With this in mind, your freezer can be stocked with a ready-made casserole for every month or even every week.

Just don't even think about skipping the thaw, unless directions clearly tell you to do so. Clear a shelf in the refrigerator and give your casserole ample time to defrost—when you do, you'll be rewarded with an evenly heated casserole that will delight friends and family.

How do you defrost your casseroles? Which recipes are currently in rotation, and what are your favorite casseroles for busy weeknights and weekend potlucks?

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