Serves 4

One of the classics of French cookery, and the ideal partner to roast lamb, or any roast meat. If you can't find Gruyère, Emmental will do.

1kg medium to large potatoes, peeled and thinly sliced (not washed)

400ml double cream

400ml milk

A good pinch of freshly grated nutmeg

2 cloves of garlic, peeled and crushed

Salt and freshly ground black pepper

250g freshly grated Gruyère

Preheat the oven to 200°C/390°F/Gas mark 6. Bring the cream and milk to the boil with the nutmeg, garlic and salt and freshly ground black pepper, then leave to cool a little. Put the sliced potatoes into a bowl and mix with a little of the cream mixture and half the cheese. Layer the potatoes in an ovenproof gratin dish, large enough to fit all the potatoes, adding a little more seasoning every couple of layers. When you have used up all the potatoes pour over the rest of the cream mixture and scatter on the rest of the cheese.

Put the gratin dish in a larger, deep-sided oven dish, then fill this with boiling water to halfway up the side of the gratin dish so you have a bain-marie. Cook in the oven for 1-1¼ hours until the potatoes are cooked through and the top is golden. Test them with the point of a knife after 1 hour. Serve immediately or cover with foil and leave in a low oven until required. E