Gratin is a culinary technique in which an ingredient is topped with a browned crust, often using breadcrumbs, grated cheese, egg or butter. The term may be applied to any dish made using this method. Gratin is usually prepared in a shallow dish of some kind. A gratin is baked or cooked under an overhead grill or broiler to form a golden crust on top and is often served in its baking dish.
A gratin dish is a shallow oven-proof container used to prepare gratins and similar dishes.