This recipe is based on a delicious dish made by Laura DaMiano, a Quebecois chef. She loves the flavor of butternut squash paired with Oka cheese, a mild, semisoft cow's-milk cheese. Mild Cheddar can be used as a substitute. If you are making this entire menu in a single oven, and you are not making the scalloped squash ahead, you can bake the squash while the ham is standing after braising.
·Squash can be baked (but not cut into rounds) 2 days ahead and cooled, uncovered, then chilled, covered. If cutting rounds, cut them out while gratin is cold, then transfer to a buttered baking sheet and reheat in lower third of a preheated 350°F oven 15 minutes. If leaving gratin whole, reheat in middle of a 350°F oven 25 minutes.
·In the photographs, we stacked 2 squash rounds for each serving. Since we needed 16 rounds to do this, we cut 15 rounds from gratin and formed 1 more round from the scraps.