Ingredients

• 1kg medium-sized Mediterranean-style potatoes, such as vivaldi, charlotte or nicola, peeled, washed, patted dry and sliced to about the size and thickness of a 50p coin
• 500ml full-fat milk
• 200g full-fat crème fraîche
• 100g gruyère cheese, freshly grated
•   salt and freshly ground black pepper
•   nutmeg, freshly grated
• 1 clove garlic, peeled
• 50g butter

Method

1. Preheat the oven to 180°C/160°C fan/gas mark 4.
2. Peel and wash the potatoes, pat dry. Slice them to about the size and thickness of a 50p coin.
3. Boil the milk, then add the crème fraîche and half the grated gruyère. Season with salt and pepper and add the point of a knife of freshly grated nutmeg.
4. Stir the potato slices into the cream and leave to cook slowly, stirring occasionally with a spatula or wooden spoon to avoid sticking, over a low heat for about 10 minutes.
5. Rub the garlic vigorously around a 2-litre ceramic or glass gratin dish, then smear with half the butter.
6. Pour the potatoes and cream into the dish and smooth the surface. Scatter the remaining cheese over the top and dot with the last of the butter.
7. Lay a sheet of tinfoil over the top and cook in the oven for 1½ hours. Remove the foil and cook for a further 15 minutes until the surface is golden.

Notes