1.Preheat oven to 180°C (160°C fan-forced). Oil a 2.5-litre (10-cup) gratin dish.
2.Using a sharp knife, mandoline or V-slicer, cut potatoes into thin slices. Pat dry with absorbent paper.
3.Combine cream, garlic, stock cubes, pepper and rosemary in a small bowl.
4.Layer a quarter of the potato slices, slightly overlapping, in dish and top with a quarter of the cream mixture. Continue layering with remaining potato and cream mixture.
5.Press potato firmly with spatula to completely submerge in cream, cover dish with foil; bake 1 hour. Remove foil and sprinkle with cheese. Bake a further 20 minutes or until potato is tender and cheese browns lightly. Stand 10 minutes before serving.