A version of gratin dauphinoise. It has two advantages over the standard method. First, preboiling the potatoes in their jackets means that there will be a potato flavour to the finished dish as well as a creamy texture. Second, it is a restaurant kitchen-friendly method in which the dish may be half prepared in advance with no loss of quality and without the need for any reheating.
1kg main-crop potatoes
175g unsalted butter
3 large cloves garlic, peeled and crushed
Salt and freshly ground black pepper
50g hard cheese (preferably Cheddar or Gruyère), grated
Wash and sort the potatoes. They need to be boiled in their skins, so it helps if they are about the same size. Boil potatoes until they are just cooked. Drain, then peel away the skin. Cut the potatoes into thickish (6mm) slices. Don't worry if a little disintegrates or if the slices are not precisely identical in size.
Melt, but do not brown, the butter with the crushed garlic in a frying pan. Unless you have a huge pan you will probably need to do this two or three times in a smaller pan. When the butter has melted and mixed with the garlic, add the potatoes and toss them. The object is to coat the slices with garlic butter, not to fry them. Season with salt and pepper and transfer to a container until needed. They will happily keep for a day like this in the fridge.
Spread the potato on to a pie dish about 2½cm deep. Pour on the milk and cream. Sprinkle cheese on top and bake at 180ºC for 20 minutes.