To make an Italian beef sandwich, preheat an oven to 250 degrees Fahrenheit. Cut slits into a 4-pound boneless rump roast, and press 6 sliced cloves of garlic into them.
Place the roast into a pan, and add 1 cup of water and 1 tablespoon each of salt, coarsely ground black pepper, crushed red pepper and dried oregano. Cover the roast with foil, and bake it for two hours with occasional basting. Allow the roast to cool completely, and slice it thinly. Serve it between two pieces of Italian bread. Add water to the pan drippings to create an au jus for dipping.
To make the beef filling in a slow cooker, bring 3 cups of water to a boil in a saucepan with 1 bay leaf and 1 7-ounce package of dry Italian-style salad dressing mix. Add 1 teaspoon each of dried oregano, basil, onion salt, parsley and garlic powder. Season it with 1 teaspoon each of salt and ground black pepper. Pour the mixture over a 5-pound rump roast in a slow cooker. Cook the roast for 10 to 12 hours on the low setting or four to five hours on high.