1 1/2 lb. boneless chuck steak (1 1/2 inch thick)
1/4 c. wine vinegar
1 tbsp. brown sugar
1 tsp. paprika
2 tbsp. Worcestershire sauce
1/2 c. ketchup
1 tsp. salt
1 tsp. mustard
1/4 tsp. black pepper

Cut the beef on a diagonal, across the grain, into slices 1 inch wide. Place these in crockpot. In a small bowl combine the remaining ingredients and pour over meat. Cover. Cook on high for 1 hour then on low for 3 to 4 hours.