How to Make It
Preheat the oven to 325°. Set the ham in a large roasting pan, fat side up. Using a sharp knife, score the fat all over in a crosshatch pattern. Pour 1 cup of the Madeira over the ham and cover tightly with foil. Bake the ham for about 3 1/2 hours, or until heated through.
In a medium bowl, toss the bread crumbs with the parsley. In a small bowl, combine the garlic, melted butter and mustard, then work into the bread crumbs with your fingers. Season with the salt.
Uncover the ham and baste with the pan juices, then transfer to a large platter. Pour the pan juices into a medium saucepan. Return the ham to the roasting pan and raise the oven temperature to 375°. Pat the bread crumb mixture all over the top of the ham, pressing it firmly into the fat. Return the ham to the oven and bake for about 30 minutes longer, or until the bread crumb coating is crisp and golden brown. Transfer the ham to a cutting board and let rest for 15 minutes.
Meanwhile, using a sharp knife, peel the oranges; remove all the bitter white pith. Working over a bowl to catch the juices, cut the oranges between the membranes to release the sections; you should have 1/2 cup of juice. Add the orange sections, orange juice and the remaining 1/2 cup of Madeira to the juices in the saucepan. Cover and simmer over low heat for 10 minutes. Remove from the heat, add the zest and keep warm.
Using a long, thin knife, carefully slice the ham, holding the crumbs in place with one hand while you cut. Arrange the ham slices on a platter. Sprinkle any fallen crumbs over the ham and serve with the orange sauce.