The reheating process for an entire casserole in the oven is easy following a few simple steps.Note: Reheating instructions and cooking times vary slightly for room temperature, refrigerated, and frozen.Note: Add ¼ cup of water to the top of a whole casserole and only 2 tablespoons for individual servings.Frozen Casserole. If it is frozen and is in a metal or disposable roasting pan, you can put it into a cold oven. Just make sure any plastic wrap has been removed and that it is covered with a lid or aluminum foil. If it is in a glass baking dish, put it in the refrigerator overnight to thaw.Refrigerated Casserole: Take it out of the refrigerator, put it in a cold or hot, 350°F oven. Reheat for about an hour.Room Temperature Casserole. Put it into a cold or hot, 350°F oven, and reheat. It takes 20-30 minutes to reheat.Heat to an internal temperature 165°F. Use an instant read thermometer to check the degrees F. You'll know it's ready if it appears hot and bubbly. Slide a knife into the center of it. If it slides in easily and comes out hot, it's ready to eat.
Microwave Instructions
The best way to reheat leftovers in the microwave oven is to reheat small portions in a microwave-safe dish.Note: Add ¼ cup of water to the top of a whole casserole and only 2 tablespoons for individual servings.Single Portions. A single portion can be reheated on high for 1-2 minute increments until it reaches the desired temperature.Large Portions. The best way to reheat a large portion in the microwave is to break it up into smaller portions and microwave it in 3-5 minute increments. This can be as easy as just taking a knife and cutting the it into smaller pieces. Separating them just slightly will allow them to reheat more evenly.
Stovetop Instructions
In order to reheat it on the stovetop, it needs to be thawed and at refrigerator temperature so that it can be removed from the storage container and placed into a large skillet. Note: Add ¼ cup of water to the top of a whole casserole and only 2 tablespoons for individual servings.Break the whole casserole up into smaller pieces and reheat at a moderate temperature (medium heat). High temperatures will cause the liquid to evaporate and it will dry out.You'll know its ready when it's hot throughout and bubbly.
Notes
General Reheating Rules of Thumb
For best results, bring the it up to room temperature before reheating.
Add a ¼ cup of water or milk to the top before you put it in the oven to reheat. The added moisture will do wonders in preventing the it from drying out.
The best way to is to cover it and put it into a cold oven. Covering the top will trap the steam in and keep it moist while it reheats.
Set the oven temperature to 350°F and heat it to an internal temperature 165°F. Use an instant read thermometer to check that the it has reached a food safe temperature.
You'll know it's ready when it is hot and bubbly. Slide a knife into the center of the dish. If it slides in easily and comes out and hot, it's ready to eat.
Pro Tip: Avoid Dry Casserole
The best way to prevent it from drying out is to add a little bit of water, around ¼ cup, to the top of it. Allow the water to seep between the food and the sides of the baking dish. Cover with aluminum foil to seal in the moisture.