1 rump roast (3 lb.)
2 small onions, chopped
1 can Coke
1/3 c. Worcestershire sauce
1 1/2 tbsp. apple cider vinegar
1 1/2 tsp. beef bouillon
1/4 tsp. dry mustard
1/4 tsp. chili powder
1/4 tsp. ground red pepper
1 c. ketchup
1 tbsp. butter

Place onions in bottom of crock-pot, then place roast on top of onions. Mix Coke and next 7 ingredients. Reserve 1 cup and refrigerate. Pour rest of sauce over roast. Cover with lid and cook by times indicated. When done, remove and shred with forks. Combine reserved sauce (1 cup), ketchup and butter. Heat and serve.