Heat oil in a large heavy pot, with a tight fitting lid, such as a dutch oven over medium heat. Trim the large pieces of fat from the roast and apply salt and pepper to taste. Brown on all sides in hot oil. Turn down the heat to low. Add the rest of the ingredients to the pot and mix lightly. Turn roast over. If the liquid does not cover the roast, add water to cover. Cover and cook for 1.5 hours. Uncover and check liquid level and turn roast over. If liquid is low, add a bit of water, enough to reach 1/2 way up the roast. Cover and continue to cook for 1.5 hours. Uncover and check for doneness. The meat should be very tender. If not, cover and cook for 1/2 hour more.