Preheat the oven to 200ºc / Gas 6. Peel the potatoes, then using a food processor or a mandolin, slice the potatoes so they are even. Bring a pan of lightly salted water to the boil and cook the potato slices for 8-10mins, or until tender. Drain and set aside.
Meanwhile, in a bowl, mix together the double cream and milk.
Grate the cheese and set aside.
In a shallow baking dish, place a layer of potatoes, then sprinkle some cheese, salt and pepper and then repeat until all the potatoes and cheese have been used and ending with cheese on top.
Carefully pour the milk mixture over the top. Bake in the oven for around 20mins or until golden brown on top. Serve hot.