Clean and trim the fat and skin from the chicken, and prepare to season.
In a large bowl, combine the chicken with Caribbean green seasoning, salt, diced onion, diced tomato, tomato ketchup, Worcestershire sauce, diced scotch bonnet pepper (if using), and black pepper. Mix well to coat the chicken evenly. Cover and refrigerate for at least 2 hours, preferably overnight.
Heat the vegetable oil in a heavy-bottomed pot over medium-high heat. Add the brown sugar and stir continuously until it becomes frothy and turns a deep amber color.
Carefully add the marinated chicken to the pot, including any marinade juices. Stir well to coat the chicken pieces with the caramelized sugar. Reduce the heat to medium, cover the pot, and cook for about 5 minutes.
Uncover the pot and increase the heat to high. Cook until the liquid reduces and the chicken is evenly browned, stirring occasionally to prevent sticking.
Add the sliced mushrooms to the pot and stir to combine. Cook for an additional 5 minutes on high heat, allowing the mushrooms to release their moisture.
Pour the water into the bowl used for marinating the chicken to collect any remaining marinade, then add it to the pot along with the coconut milk. Stir well, bring to a boil, then reduce the heat to low, cover, and simmer for 8–10 minutes, or until the chicken is fully cooked.
Remove the lid and increase the heat to help thicken the gravy to your desired consistency. Taste and adjust salt if necessary.
Add the green olives and chopped parsley to the pot. Stir well and cook for an additional 3–5 minutes.
Serve hot over steamed rice or your preferred side dish.
