What a robust sandwich,
 and it's easy to fix a for a hungry bunch. 

3 cups celery chopped
1 cup onion chopped 
1 cup ketchup 
1 cup barbecue sauce 
1 cup water
2 tablespoons vinegar
2 tablespoons Worcestershire sauce 
2 tablespoons brown sugar 
1 teaspoon chili powder 
1 teaspoon salt 1/2 teaspoon pepper or to taste
1/2 teaspoon garlic powder 
1 boneless chuck roast { 3 to 4 pounds } ~ trimmed of fat
8 hamburger buns ~ split 
In a slow cooker, combine the first 12 ingredients; mix well. Add roast. Cover and cook on high for 6 ~ 7 hours or until tender. Remove roast; cool. Shred meat and return to sauce; heat through. Use a slotted spoon to serve on buns. 8 servings. Easily doubled for a crowd.

The Lighter Side;
Boneless Chicken 
Whole wheat hamburger buns