BBQ Roast Beef Sandwiches 14 Sep 11

3 lb roast
1-1/2 cups chopped onion
1/2 cup packed brown sugar
2 tbsp chili powder
1 tsp salt
1 tsp dry mustard
1 can tomato paste
1/4 cup vinegar

Follow list to add ingredients. Cook 8 hours on high in crockpot. Separate with fork. Serve on hamburger buns.