The word gratin derives from the French word grater or gratter, which means to scrape. The French have been baking casseroles in low-sided baking dishes, also called gratins, for centuries. They may be served with a salad for lunch (see the potato and ham gratin below), as a side dish to a roast at dinner, or even, when made with fruit, for dessert. All have in common a crisp, browned crust, sometimes made with the help of bread crumbs or cheese.
While many foods can be prepared as gratins, the best known are made with potatoes, a New World tuber that was not widely accepted for culinary purposes in France until the 17th century. The first French reference to a potato gratin dates from July 12, 1788, when one was served at a dinner for municipal officials in the Dauphine region of southeastern France. The gratin Dauphinoise was born, in which thinly sliced potatoes are slowly baked in cream with a faint hint of garlic. Neighboring Savoie soon offered the gratin Savoyard, which replaced the cream with bouillon and added cheese.
French food authority Patricia Wells, writing for the New York Times (November 30, 1986), describes the French culinary clamor that surrounds the dish, “But without question, the real king of gratins is the potato gratin, about which there is no end of gastronomic debate. What’s the best potato? Should one add cream or should it be milk?Should you cook the potatoes first or just leave them to absorb the liquid slowly as they bake? Should they be washed or left wholesomely alone, so that the potato starch will cling naturally to the accompanying liquid? Should the oven be a scorchingly hot one or a gentle slow one, and should cheese be allowed? Is it heresy to admit a bit of egg to enrich an already elaborate dish?”
The recipes that follow are global, and confound the French boundaries for potato gratins even further.