Step 1

Preheat oven to 325°F. Place lasagna in an oven-safe dish, sprinkle with a little water or sauce, wrap in aluminum foil, and bake until the lasagna is heated through, up to 45 minutes for larger portions.

Step 2

Whether your frozen lasagna was previously baked or not, start by thawing the lasagna in the refrigerator overnight. (If you don’t have time to defrost your frozen lasagna, it can go straight in the oven, but keep in mind that frozen lasagna can take up to twice as long to reheat as defrosted lasagna.)

Step 3

The next day, let the lasagna sit at room temperature for about 30 minutes while the oven preheats. Remove any plastic wrap, then wrap the lasagna in aluminum foil and bake according to the original recipe (for lasagnas that were not previously baked) or at 375°F until heated through, which will likely take about an hour.

Step 4

To brown the top, remove the foil and bake for another five to ten minutes.