Gruyère Gratin Dauphinois

Preheat the oven to 180°C (Gas Mark 4). Peel the potatoes, then slice them finely (about 4mm thick – a mandolin is good for this). Melt the butter in a small pan, then brush half of it all over the insides of a wide, shallow gratin dish. Crush the garlic cloves and spread them across the base of the dish, then arrange the potato slices across the bottom of the dish, overlapping them slightly like fish scales. Season with salt, pepper and grated nutmeg, then arrange another layer on top. Season as before, and keep going until you have used up all the potato slices, seasoning each layer. Next, tip the cream into the pan with the remaining melted butter, swirl to mix, then pour over the potatoes. Grate the Gruyère cheese and scatter it across the top, then cover the dish with foil and bake in the hot oven for an hour. Remove the foil, return the dish to the oven and cook for about 20 minutes more, or until the potatoes are golden brown on top.