Rub the oxtail with salt, pepper, minced garlic, thyme, bouillon powder, and green onions. Tightly cover and refrigerate for at least 2 hours or overnight. When ready to cook, remove from the fridge and shake off any visible onions or herbs from the oxtail meat. Set aside. (See notes 1)
In a large pot, heat oil over medium heat until hot, and then saute the oxtail, frequently stirring while scraping any browned bits off the bottom of the pot until the oxtail pieces are browned. If desired, drain the oil, leaving 2-3 tablespoons.
Add onions, garlic, thyme, pimento seeds, or allspice, then stir for about a minute. Throw in the browned oxtails, followed by Worcestershire sauce, browning sauce, tomato paste, bouillon powder, curry powder, green onions, and stir for another minute.
Then add about 4-6 cups of water; it's best to start with 4 cups, then add as needed.
Bring to a boil and simmer until tender (depending on the oxtail size) for about 2-3 hours (4-5 hours at high altitude), occasionally stirring, so it doesn't stick to the pan.
About 20-30 minutes before removing it from the heat, add the broad beans and scotch bonnet pepper. Adjust the thickness of soup with water or stock.
Simmer 20-30 minutes, and adjust salt to taste.