Preheat the oven to 180C/350F/Gas 4.
Heat the cream and garlic in a pan until gently simmering. Add the sliced potato, and season well with salt and freshly ground black pepper.
Stir in half the cheese, then transfer the mixture to a gratin dish and sprinkle over the remaining cheese. Bake in the oven for 15 minutes, or until golden-brown and bubbling on top. Serve immediately from the dish.