Question: how long does it take to cook frozen lasagna in the oven?
Answer: Preheat the oven to 375 degrees. Remove plastic wrap and foil from baking dish and replace foil. Place dish on a rimmed baking sheet and bake for 1 hour if thawed, 1 1/2 hours if frozen. Remove foil and continue baking until lasagna is bubbling and cheese is browned.