1. With a fine knife, make slashes about 2 inches deep along the loin, almost to the center of the meat. Season the shrimp and egg with salt and pepper. With your fingers, stuff half the slashes with the shrimp, the other half with chopped egg, or mix the shrimp and egg together and use as a stuffing. Season the loin with salt, pepper and garlic.
2. Heat 3 tablespoons of butter in a flameproof casserole large enough to hold the loin and sauté the meat untilgolden. Pour the wine and bring to a simmer. Remove from the heat. Cover with aluminum foil and the casserole lid; bake in a moderate (325º) oven for 2 hours, or until the pork is tender. Lift the pork onto a warmed serving platter. Slice the pork and keep warm.
3. In a saucepan pour the cooking liquid of the pork and mix the flour with the remaining tablespoon of butter; stir over moderate heat until the sauce is slightly thickened. If the sauce is too thick, add a little wine or chicken stock.
4. Correct seasonings. Spoon a little of the sauce over the pork slices, and pour the rest into a sauce boat.