How do restaurants reheat lasagna?

Online Answer
Usually, at a restaurant, they reheat lasagna in a preheated oven, after adding more cheese and sauce on top. Their secret (so that it does not dry out) is to put about 3 tablespoons of water or tomato sauce per serving on top of the lasagna. They then wrap it in plastic wrap and heat it for 5 minutes.
Related Questions 📌
Preheat the oven to 400 degrees Fahrenheit. Bake an 8-inch square pan of lasagna for 40 to 50 minutes. A refrigerated lasagna in a 9- by 13-inch baking pan will need between 55 and 70 minutes, while a jumbo-sized pan needs 70 to 85 minutes..
Cooking Frozen Lasagna. Cooking frozen lasagna is absolutely doable and it really is pretty simple. If you want to cook it without thawing it, no problem. You will need to plan probably about 90 minutes of baking time if you are going to bake it from a frozen state.
A: Soupy lasagna is either a result of wet noodles that were not drained properly or lasagna was layered with too much (thin wet) sauce. ... The problem is probably that the noodles are too wet when the lasagna is being assembly. Our best advice is to drain and rinse the cooked noodles, using a colander.
We know you're as eager as we are about cutting into that lasagna, but you have to wait. Better still (if you have the time), consider making your lasagna a day ahead of time and reheating to serve..
Start by spreading a layer of your tomato-based sauce (either a plain tomato sauce or your pre-made ragù) on the bottom of your dish. Next, add a single layer of pasta sheets. Then, add a layer of white sauce, followed by another single layer of pasta sheets.