175ml double cream
7 garlic cloves, finely chopped, plus one halved
Peel and finely slice the potatoes. Using a tea towel dry the potatoes, to remove excess starch. Put the potatoes in a large pan, and pour in the cream and milk. Bring to the boil, stirring to make sure nothing sticks to the bottom of the pan. Make sure the milk and cream doesn't burn. Add the garlic and leave to simmer for 40 minutes.
Preheat the oven to 180°c.
Rub the halved garlic around the baking dish.
Using a slotted spoon, remove the potatoes and place in the garlic rubbed dish. Pour the cream, over the top until the potatoes are covered. Dot with butter. Bake until the top is golden.