Season the oxtails

• Pat the oxtails dry and place them in a bowl.
• Rub them with browning sauce, soy sauce, Worcestershire sauce, minced garlic, allspice, black pepper, salt and brown sugar.
• Add the chopped onion, scallions and thyme and toss to coat.
• Let the meat marinate so the flavors soak in.

Sear the oxtails

• Heat the oil in a frying pan over medium-high heat.
• Sear the oxtails on all sides until deeply browned.
• Work in batches so the meat browns instead of steaming.

Load the slow cooker

• Transfer the seared oxtails and all the marinade into the slow cooker.
• Pour in the beef stock.
• Add the butter beans.

Slow cook until tender

• Cover and cook on low until the meat is falling off the bone and the sauce is rich.
• Stir once or twice during cooking.

Thicken the gravy

• Whisk the cornstarch slurry into the cooking liquid.
• Cook uncovered until the gravy thickens and coats the meat.

Serve

• Spoon the oxtails and gravy over rice.
• Spoon the butter beans alongside and serve hot.