Marinate the beef short ribs in soy sauce and garlic for at least 1 hour or overnight for deeper flavor.
Heat the cooking oil in a large pot over medium-high heat and sear the short ribs until browned on all sides.
Add the remaining marinade, vinegar, bay leaves, and black peppercorns to the pot.
Pour in enough water or beef broth to partially cover the meat and bring to a boil.
Reduce the heat to low, cover, and simmer for 2½–3 hours, or until the beef is fork-tender.
Remove the lid and continue simmering for 10–15 minutes until the sauce thickens slightly and coats the meat.
Serve hot with steamed white rice and garnish with chopped spring onions if desired.