Preheat oven to 325 degrees F. Season beef with some salt and pepper. In Dutch oven heat oil over medium-high heat. Brown beef well on both sides. Remove from pan; set aside.
Cook bacon in pan until lightly browned. Add onion and garlic; cook about 5 minutes or until onion is tender. Stir in vinegar, 2 cups of the berries, sugar, and the 1/2 teaspoon salt. Bring to boiling; stir to dissolve sugar. Reduce heat; boil gently, uncovered, 10 minutes. Return beef to pan. Cover; roast 2 1/2 to 3 hours or until tender.
Remove meat from pan, reserving liquid; thinly slice against grain. Skim off fat; stir in remaining berries. Serve meat on buns with reserved liquid. Top with sprouts, if desired.