Place the 3 lbs of bone-in oxtail pieces in a large bowl. Add the browning sauce, soy sauce, minced garlic, grated ginger, salt, and pepper. Massage until fully coated and let marinate for at least 30 minutes.

Heat vegetable oil in a large Dutch oven over medium-high heat. Sear the oxtails in a single layer for 3-4 minutes per side until a dark mahogany-brown crust forms. Remove and set aside.

Sauté the chopped yellow onion in the same pot for 2 minutes. Return the oxtails to the pot, pour in the beef broth, add the Scotch bonnet pepper, and drop in 3 sprigs of fresh thyme.

Bring to a boil, then immediately reduce heat to low. Cover tightly and simmer for 2.5 to 3 hours until the meat is fork-tender but still clinging to the bone.

While braising, combine the rinsed long-grain rice, undrained kidney beans, coconut milk, 1 cup of water, and a pinch of salt in a saucepan. Bring to a boil, cover, reduce heat to low, and steam for 20 minutes until fluffy and light brown.

Once oxtails are tender, stir the cornstarch slurry directly into the pot. Simmer uncovered for 5-10 minutes until the liquid reduces to a thick, glossy brown gravy.

Gently fold in the drained butter beans. Simmer for 3 minutes until heated through, maintaining their pale yellow color.

Serve the oxtails and glossy gravy over the rice and peas. Garnish with diagonally sliced fresh green scallions and a sprig of fresh green thyme.