Sprinkle roast on all sides with salt & pepper. Place roast in crockpot, add onion, broth, brown sugar & vinegar. Cover tightly, cook 5-6 hours on high. Remove roast & set aside. Add crumbled gingersnaps to the sauce in the crockpot. Stir until sauce thickens. Slice meat and serve sauce over slices. Serve with noodles.