Preheat the oven to 170C/325F/Gas 3.
Rub a gratin dish liberally with the garlic and butter.
Layer the potatoes into the dish, making sure each layer is seasoned.
Pour over the cream and cook in the oven for 1¼ hours.
Turn up the heat to 200C/400F/Gas 6 and cook for a further 15 minutes until the top is golden. Serve.
Sprinkle grated cheese over the top of your potato gratin before cooking for an extra treat.