In a small saucepan, combine the cream, broth, garlic, sage, and
Cut the rounded ends off of each potato, then peel the potatoes. Using a food processor or mandoline fitted with the slicing blade, cut the potatoes crosswise into slices ¼ inch (6 mm) thick. Layer the potato slices, alternating types, in the prepared baking dish. Pour the warm cream mixture through a fine-mesh sieve evenly over the potatoes and discard the garlic and sage. Cover the dish tightly with foil and bake for 45 minutes.
Uncover and sprinkle the potatoes with the cheeses. Continue to