How Long Do You Heat Cold Lasagna?
If your lasagna is fully cooked but just needs reheating, you should cover the lasagna with foil and bake it in a preheated oven at 350°F for approximately 30 minutes. If the lasagna is still cold and frozen, it will take longer, around 1 hour or more, depending on the size and depth of the dish. Always make sure to check the internal temperature of the lasagna, which should reach 165°F.