Season the roast with pepper, place in pan and roast, uncovered in 475ºF. oven until both sides are browned and turning once about 4 to 5 minutes each side. Remove from oven, pour vinegar and water over roast. Arrange onion slices on top, add bay leaves to the pot liquid. Cover and return to oven. Reduce heat to 350ºF. and cook 1 1/2 hours or until tender. Add ginger snaps and cook 1/2 hour longer. Additional water may be added for thinner gravy.