Preheat the oven to 200°C (400°F).
Wash, peel and cut the potatoes into thin slices (2 to 3 mm thick).
Cut the onion into quarters and roughly crush the garlic cloves.
In a pan mix the milk and cream. Add the onion and garlic cloves. Bring to boil and leave for 5 minutes. Remove the cloves and onion.
Add the potato slices, season with salt and pepper and cook over low heat for 15 minutes.
Put the potatoes and the milk/cream mixture in an ovenproof dish.
Bake for 40 minutes, until the potatoes are tender.
