It is a cooking technique in which a meal is covered with sauce or grated cheese and given a heat stroke to dorate it; it is also known as gratin. Festively it is used as "free", "do something at no cost", by the resemblance of voices. It comes from the French au gratin, with the same meaning, which originates from the ancient word gratter ( "raer , especially the crust of food stuck at the bottom of the pot") . See gratin .
