Brown meat on all sides in oil in large skillet, Remove meat to large bowl or large pot and let cool to lukewarm.
Add marinade ingredients to skillet and bring to a boil, mixing well. Turn off heat as soon as mixture boils, and let cool to room temperature. Pour over meat in large bowl, cover with cellophane wrap and place in refrigerator for at least 2 days.
TO cook: arrange vegetables around meat in roasting pan. Fill with marinade to within 2” of top of pan. Bake at 325º for 2-1/2 hours. Remove meat and vegetables to platter and keep warm while making gravy. Add 2 tablespoons cornstarch for each 1 cup of marinade-juice from roasting pan and stir until mixture thickens. Allow to simmer for several minutes, then pour over meat and vegetables.