Heat oven to 180C/160C fan/gas 4. Bring a pan of salted water to the boil and cook the potato slices for 3 mins. Drain and cool.

Butter a shallow ovenproof dish and spread over the garlic. Layer the potatoes, leeks and cheese, season well, then pour over the cream. Cover with foil and bake for 1 hr.

Remove the foil and continue cooking for 20 mins or until the top is browned and the potatoes are cooked through. Leave to stand for 5 mins before serving.