Goat meat is naturally tough, so the key is to marinate it overnight (or at least 4 hours) and then slow-braise it for a long time. Using Jamaican curry powder or a strong 'Madras' style curry powder is essential. The process of 'burning the curry' in oil at the start deepens the flavor profile of the curry.
Clean the meat by washing it with a mixture of water and lime juice (or vinegar), rinse, and pat dry.
In a large bowl, combine the goat meat with the curry powder, thyme, garlic, ginger, allspice berries, scallions, salt, and pepper. Mix well.
Cover and refrigerate to marinate for at least 4 hours, preferably overnight. Take the meat out of the fridge 30 minutes before cooking.
In a large, heavy-bottomed pot or Dutch Oven, heat the oil over medium-high heat.
Add the 2 tablespoons of curry powder. Stir rapidly for 30 seconds until the curry is highly fragrant and slightly darkens (this is 'browning the curry' and prevents a 'raw' spice taste).
Add the diced onion and cook for 5 minutes until soft. Add the marinated meat and sear for 10 minutes, stirring frequently. The meat should brown and release its marinade liquid.
Add the water or broth. Place the whole Scotch Bonnet pepper (be careful not to break it!) and the remaining thyme sprigs into the pot.
Bring to a boil, then reduce the heat to minimum, cover, and simmer for 1.5 to 2 hours. The meat should be almost completely fork-tender.
Uncover and add the chopped potatoes and the coconut milk. The potatoes should be submerged under the liquid. If the sauce is too thick, add a little more water.
Cover and cook for another 20-30 minutes until the potatoes are soft and the gravy has thickened. Remove the Scotch Bonnet pepper (if whole) and thyme sprigs before serving.
Serve hot with Rice and Peas.