Chard and Rosemary Gratin

If you–ve got a whole head of Swiss chard or loose leaves with fat stalks, use the whole thing and cook the stalks too. If you–ve got leaves with very skinny, stringy stalks, these aren–t worth bothering with; remove and discard them and use a few more leaves instead. Serve this as a vegetarian main course, accompanied by crusty bread, boiled potatoes or rice, or alongside a roast or quick grilled lamb chops.