Preheat oven to 350F.

Liberally season oxtails with garlic salt and black pepper.

Pour water ¾ inch deep into large, deep roasting pan. Pan must be large enough to hold oxtails in a single layer, and there must be enough liquid to almost submerge the oxtails without overflowing. Add ½ cup of bouillon powder and 1 tbsp Kitchen Bouquet and whisk to combine.

Place large, deep skillet or Dutch oven over medium-high heat and add vegetable oil. When oil is shimmering, working in bathes, add oxtails and cook until browned on all sides, 5-7 min each batch. Transfer to roasting pan with broth, leaving fat in skillet. Remove skillet from heat and reserve.

Top oxtails evenly with ½ cup of onion and 2 tbsp garlic. Cover pan, transfer to oven, and cook until fork-tender, about 2.5 hours.

Return skillet with fat to medium heat. Add remaining ½ cup onion, 2 tbsp garlic, 1 tsp Kitchen Bouquet, and habanero. Cook stirring for 2 minutes. Add flour, curry powder, cayenne and remaining ¼ cup bouillon powder and cook, stirring constantly until well-mixed and flour is toasted, about 5 minutes.

Add warm water, a little at a time, while stirring constantly to get rid of clumps. Once all incorporated, add curry paste and whisk to combine. Turn the heat to a bare simmer, cover pan, and cook stirring occasionally, until just thickened, about 20 minutes. Remove from heat and set aside, covered, until oxtails have finished cooking.

Transfer oxtails to curry. Turn the heat to a gentle simmer, add 3 cups of broth from the roasting pan, and stir. Turn heat to low, cover and cook until the oxtails are completely tender, about 1 hour. Stir occasionally. If curry gets too thick, add a splash of broth.