This one is made with Taleggio, a creamy Italian cheese that melts beautifully and has a marvelous, delicate flavor. It isn’t always easy to find, especially outside of large cities. If you can’t find it where you live, substitute Fontina (preferably Italian) or a mixture of Fontina and Bel Paese. The flavors of the clarified butter and sage are perfect with both the cheese and the potatoes.