Peel the potatoes, cut them into very thin slices and pat dry in a cloth. One of those vegetable slicers – sometimes called a ‘mandolin slicer’ – is really very useful when preparing the potatoes for this dish. Crush the clove of garlic and rub round the inside of an earthenware baking dish. Generously butter the dish with about half the butter.
Arrange rows of potato slices in the dish