Rinse oxtails with water and vinegar and pat dry. Cover oxtails with brown sugar, soy sauce, Worcestershire sauce, salt, garlic powder, black pepper, all-spice, and browning and rub into oxtails.
Set Pressure Cooker on High Sauté and once hot, add vegetable oil. Next, add your larger oxtail pieces to the pot, flat side down about ¼ inch apart, and brown on each side.
Remove oxtail after browning and place in bowl.
Deglaze your pressure cooker by adding about 2 Tbsp of beef broth to the insert. Take a wooden spoon and deglaze your pot by removing the brown bits at the bottom. Then add your yellow onions, green onions, carrots, garlic, and scotch bonnet pepper. Stir and sauté for about 5 minutes or until the onions have softened.
Add dried thyme, oxtails, remaining beef broth, and ketchup to the pressure cooker insert.
Press “Cancel” on your Instant Pot. Cover and cook on high pressure for 45 minutes. Once timer is done, allow pressure cooker to naturally release.
Once all pressure has released, open lid and remove oxtails and vegetables, leaving liquid behind. Turn Pressure Cooker on sauté. Once liquid begins to simmer, create a corn starch slurry by combining corn starch and water to a separate bowl. Stir into simmering liquid. Add drained butter beans into pressure cooker and allow to simmer for about 5 minutes, until liquid is slightly thickened and butterbeans are warmed.
Add oxtails and vegetables back to the pressure cooker. Serve and enjoy :)