Pat short ribs dry. Season with salt and pepper. Sear in batches in hot oil for 2 to 3 minutes per side until deeply browned on all surfaces.
In same skillet, cook garlic 1 minute. Add white vinegar and scrape up browned bits. Add soy sauce, rice wine vinegar, brown sugar, and oyster sauce. Stir until sugar dissolves.
Pour sauce into slow cooker. Add water, whole peppercorns, and bay leaves. Place seared short ribs bone side up in the sauce.
Cover and cook on LOW for 7 to 8 hours until meat is completely tender and pulling away from the bone.
Remove ribs carefully. Discard bay leaves and peppercorns. Transfer braising liquid to a saucepan. Skim fat. Bring to a simmer.
Whisk in cornstarch slurry. Cook 4 to 5 minutes until sauce is deeply glossy and coating. Taste and adjust seasoning.
Arrange short ribs over steamed jasmine rice. Spoon adobo sauce generously over the top. Garnish with parsley or green onions.
