01 - In a large bowl, combine the chicken pieces with curry powder, salt, black pepper, minced garlic, grated ginger, thyme sprigs, chopped Scotch bonnet pepper, and lime juice. Toss until every piece is evenly coated. Cover tightly and refrigerate for at least 1 hour, or overnight for the most flavorful results.
02 - Heat the vegetable oil in a large Dutch oven or deep heavy-bottomed skillet over medium heat. Sprinkle in the remaining 2 tablespoons of curry powder and stir constantly for 1 to 2 minutes until deeply fragrant and slightly darkened, taking care not to let it scorch.
03 - Add the marinated chicken pieces to the pot, shaking off excess marinade but reserving the liquid. Sear the chicken in the toasted curry base, turning occasionally, until lightly browned on all sides, approximately 5 minutes.
04 - Add the sliced onion, chopped scallions, and bell pepper to the pot. Cook for about 3 minutes, stirring frequently, until the vegetables have softened and released their fragrance.
05 - Pour in the reserved marinade liquid and chicken broth. Drop in the diced potatoes, thyme sprigs, and allspice berries if using. Stir everything together thoroughly, bring to a gentle simmer, then reduce the heat to low and cover with a tight-fitting lid.
06 - Cook covered for 30 to 35 minutes, stirring occasionally to prevent sticking. The chicken should be cooked through, the potatoes fork-tender, and the sauce naturally thickened. Taste and adjust salt and pepper as needed.
07 - Remove the pot from heat and let rest for a few minutes. Garnish with fresh scallion or a sprig of thyme if desired. Serve hot alongside steamed white rice, Jamaican rice and peas, or fried plantains.