Gratin

A gratin is any dish baked in a wide, shallow dish until a browned crust forms on top. The crust may be cheese, breadcrumbs, butter, or just cream that has browned. The best-known is potato gratin, thinly sliced potatoes baked in cream or milk. "Gratin" is also the name of the shallow dish itself.

How to do it

1. Heat the oven to 160 to 180°C (325 to 350°F).
2. Slice 1 kg (2 lb) of waxy or all-purpose potatoes about 3 mm (⅛ inch) thick. A mandoline gives even slices. Do not rinse them; the starch thickens the cream.
3. Rub a shallow dish with garlic and butter.
4. Layer the potatoes, seasoning each layer with salt, pepper and a little nutmeg.
5. Pour in about 500 ml (2 cups) of cream, or a mix of cream and milk, warmed with garlic, until it nearly covers the top layer.
6. Bake for 1 to 1½ hours.
7. If the top is pale, broil (grill in the UK) for 2 to 3 minutes. Rest for 10 to 15 minutes before cutting.

How to tell it is done

A knife slides through every layer with no resistance; the potatoes are fork-tender. The top is golden brown with darker edges, and the cream has thickened around the slices instead of pooling.

Common mistakes

• Uneven slices. Thick ones stay hard while thin ones go to mush.
• A deep dish. You get less crust and a longer, uneven bake.
• Too hot an oven. Cream can split and the top burns before the middle cooks.
• Cutting it right away. It needs to rest to firm up.

In recipes

"Au gratin" means a dish topped with cheese or breadcrumbs and browned, which is the method called gratinating. Gratin dauphinois is the French classic: potatoes, cream and garlic, often without cheese. Many vegetable gratins, such as cauliflower, use a cheese béchamel as the sauce. Leftovers keep in the fridge for 3 to 4 days.