Instructions
Step 1
Make the marinade: To a food processor, add the soy sauce, allspice, garlic, scallions, ginger, Scotch bonnet, onion, and MSG if desired and process into a coarse paste, about 1 minute. Transfer 1 cup of the marinade to a small container for the braising liquid, cover, and refrigerate. To a 9- by 13-inch baking dish, add the oxtail and coat thoroughly with the remaining marinade. Cover and refrigerate for at least 4 hours, or preferably 8.
Step 2
Braise the oxtail: Position a rack in the middle of the oven and preheat to 425°F. Remove the oxtail from the marinade and pat dry. Transfer to a roasting pan and bake until browned, 20–25 minutes.
Step 3
Meanwhile, to a large pot over medium-high heat, add the oil, carrot, celery, and onion and cook, stirring frequently, until the vegetables soften slightly, about 5 minutes. Add the tomato paste and cook, stirring occasionally, until it darkens, 2–3 minutes. Stir in the thyme, bay leaves, and reserved marinade and cook until the marinade thickens slightly, 1–2 minutes. Add the rum, scraping up any browned bits, and continue cooking until mostly evaporated, 1–2 minutes more.
Step 4
Transfer the roasted oxtail and any pan drippings to the pot and add enough water to cover the oxtail completely, 6–8 cups. Add the allspice if desired and season lightly with salt and black pepper. Bring to a boil, then turn the heat to medium-low, cover, and simmer until the meat breaks apart easily when pierced with a fork, 1½–2 hours.
Step 5
Make the pickled onions: In a medium bowl, stir together the vinegar, sugar, salt, and 1 cup of room-temperature water until the sugar and salt are dissolved. Stir in the onion and set aside.
Step 6
Make the oxtail barbecue sauce: Place a large strainer over a second large pot and strain the braised oxtail mixture through it. Transfer the oxtail to a plate and set aside. Discard the remaining solids. Bring the braising liquid to a boil, turn the heat to medium-low, and simmer, stirring occasionally, until reduced by half, 1–1½ hours.
Step 7
Stir in the barbecue sauce, bring back to a simmer, and cook, stirring occasionally, until reduced slightly, 10–15 minutes. (The sauce should be thick enough to coat the back of a spoon. If not, transfer 1 cup of the sauce to a small bowl and whisk in the cornstarch until smooth. Pour the mixture back into the pot and continue simmering, stirring occasionally, until the sauce reduces and thickens slightly, about 10 minutes more.)
Step 8
Heat a grill to medium-high. Grill the oxtail, basting with the oxtail barbecue sauce and flipping once, until the sauce is sticky and slightly charred, about 3 minutes per side.
Step 9
Transfer the oxtail to a platter, drizzle with extra barbecue sauce, and garnish with the pickled onions and mint.
Make the marinade: To a food processor, add the soy sauce, allspice, garlic, scallions, ginger, Scotch bonnet, onion, and MSG if desired and process into a coarse paste, about 1 minute. Transfer 1 cup of the marinade to a small container for the braising liquid, cover, and refrigerate. To a 9- by 13-inch baking dish, add the oxtail and coat thoroughly with the remaining marinade. Cover and refrigerate for at least 4 hours, or preferably 8.
Braise the oxtail: Position a rack in the middle of the oven and preheat to 425°F. Remove the oxtail from the marinade and pat dry. Transfer to a roasting pan and bake until browned, 20–25 minutes.
Meanwhile, to a large pot over medium-high heat, add the oil, carrot, celery, and onion and cook, stirring frequently, until the vegetables soften slightly, about 5 minutes. Add the tomato paste and cook, stirring occasionally, until it darkens, 2–3 minutes. Stir in the thyme, bay leaves, and reserved marinade and cook until the marinade thickens slightly, 1–2 minutes. Add the rum, scraping up any browned bits, and continue cooking until mostly evaporated, 1–2 minutes more.
Transfer the roasted oxtail and any pan drippings to the pot and add enough water to cover the oxtail completely, 6–8 cups. Add the allspice if desired and season lightly with salt and black pepper. Bring to a boil, then turn the heat to medium-low, cover, and simmer until the meat breaks apart easily when pierced with a fork, 1½–2 hours.
Make the pickled onions: In a medium bowl, stir together the vinegar, sugar, salt, and 1 cup of room-temperature water until the sugar and salt are dissolved. Stir in the onion and set aside.
Make the oxtail barbecue sauce: Place a large strainer over a second large pot and strain the braised oxtail mixture through it. Transfer the oxtail to a plate and set aside. Discard the remaining solids. Bring the braising liquid to a boil, turn the heat to medium-low, and simmer, stirring occasionally, until reduced by half, 1–1½ hours.
Stir in the barbecue sauce, bring back to a simmer, and cook, stirring occasionally, until reduced slightly, 10–15 minutes. (The sauce should be thick enough to coat the back of a spoon. If not, transfer 1 cup of the sauce to a small bowl and whisk in the cornstarch until smooth. Pour the mixture back into the pot and continue simmering, stirring occasionally, until the sauce reduces and thickens slightly, about 10 minutes more.)
Heat a grill to medium-high. Grill the oxtail, basting with the oxtail barbecue sauce and flipping once, until the sauce is sticky and slightly charred, about 3 minutes per side.
Transfer the oxtail to a platter, drizzle with extra barbecue sauce, and garnish with the pickled onions and mint.

