Make Ahead Mac and Cheese

1. Pulse bread, Parmesan, garlic and 2 Tbs butter in food processor until coarsely ground. Divide crumb mixture between 2 zipper lock freezer bags and freeze. 2. Bring 4 quarts water to a boil in Dutch oven over high heat. Add 1 Tbs salt and macaroni and cook until barely softened, about 3min. Drain pasta, then spread out on rimmed baking sheet and let cool. 3. Heat remaining butter, flour, mustard, and cayenne in empty pot over medium-high heat, stirring constantly, until golden and fragrant, 1-2minutes. slowly whisk in broth and cream and bring to boil. Reduce heat to medium and simmer until slightly thickened, about 15minutes. Off heat, whisk in colby, cheddar, 1 teaspoon salt, pepper and ham if using. 4. Stir cooled pasta into sauce, breaking up any clumps, until well-combined. Divide pasta mixture between two 8-in square baking dishes. Cool to room temperature, about 2 hours. Wrap dishes tightly with plastic, cover with foil, and freeze for up to 2 months. 5. Adjust oven rack to middle position and heat oven to 375degrees. Remove foil from casserole and reserve. Microwave casserole until mixture is thawed and beginning to bubble around edges, 7-12 minutes, stirring and replacing plastic halfway through cooking. (If preparing both dishes, microwave one at a time.) Discard plastic and cover pan with reserved foil. Bake 20 minutes, then remove foil and sprinkle with 1 bag frozen bread crumbs. Continue to bake until crumbs are golden brown and crisp, about 20minutes longer. Let cool 10 minutes. Serve.