Mix the Marinade: In a large non-reactive bowl, whisk together vinegar, water, onions, salt, pepper, sugar, cloves, and bay leaves until well combined.

Marinate the Roast: Add the beef rump roast, cover, and refrigerate for 2–3 days. Turn the meat daily to ensure even flavor penetration.

Brown the Beef: Remove the roast, pat dry, and sear all sides in a hot Dutch oven with a splash of oil until golden.

Slow Cook: Pour the reserved marinade over the roast. Bring to a simmer, cover, and cook on low heat for about 4 hours or until the meat is fork-tender.

Prepare the Gravy: Strain the cooking liquid into a saucepan. Bring to a gentle boil and whisk in a roux (butter + flour) until the sauce thickens into a silky gravy.

Slice and Serve: Cut the roast across the grain into thin slices, spoon the tangy gravy over top, and garnish with fresh herbs if desired.