Lay the pork on a cutting board and season with salt and pepper. In a mixing bowl, stir together 1/2 cup of the parsley, the pine nuts, currants, and 1/2 cup of the pecorino and season with salt and pepper. Lay the prosciutto slices over the pork piece to cover completely. Sprinkle the parsley mixture evenly over the prosciutto. Arrange the eggs in two rows across the meat. Grate nutmeg over the other piece and sprinkle with two tablespoons of the oregano, rubbing it between your fingers to release the essential oils. Carefully roll the piece up like a jellyroll and tie firmly with butcher's twine in several places. Season with salt and pepper.
In an 8-quart Dutch oven, heat the oil until smoking. Carefully brown the pork roll on all sides, taking your time to get a deep golden brown; this should take 15 to 20 minutes. Remove the meat and set aside.
Add the onions, remaining 2 tablespoons of oregano, and the garlic to the pan and cook until light golden brown and soft, about 9 to 11 minutes. Add the wine, tomatoes, and pepper flakes and bring to a boil. Return the pork to the pan and simmer, partially covered, for 1 hour and 20 minutes, moving occasionally to avoid sticking.
Transfer the pork to a cutting board and remove the butcher's twine carefully. Slice the braciolona 3/4–inch thick with a very sharp knife. Arrange like shingles on a warm platter and sprinkle with the remaining 1/4 cup of grated pecorino and remaining chopped parsley. Cover and keep warm if serving after the pasta course.
Recipe courtesy of Mario Batali