Combine onions, garlic, carrots, celery and pepper in a large bowl. Season the meat with salt and pepper, and toss meat with the vegetables. (Protect yourself from contact with Scotch Bonnet peppers.) Cover and marinate in the refrigerator for at least 2 hours, (the longer the better).
Heat the oil and butter in a large saucepan, and add the meat/vegetable mixture, browning all sides of meats and cooking for a few minutes to integrate flavors. Add the tomato paste and stock, cover and reduce heat. Simmer until meat is fork tender, at least 1 1/2 to 2 hours, checking occasionally to make sure there is adequate liquid in the pot. (This recipe is also great cooked slowly in a crock pot.) Once the meat is tender, add the chopped tomato and parsley and serve.