This delicious recipe is adapted from award-winning chef and food writer Jennifer McLagan. It's a variation on the classic Pommes Anna, a "cake" made with thinly sliced potatoes drizzled with butter and baked in a pan. This version is made with sweet potatoes, butternut squash, and apple, in addition to potatoes, with with our Graisse de Canard instead of butter. The rich, complex, sweet and savory flavors make this dish sing. It's the perfect partner for roasted poultry or meat and can be prepared in advance and reheated in the oven.