Cut the strips of ribs into manageable pieces, with about 3-4 ribs to each piece, then put the ribs in a large saucepan with the onions, garlic, a generous pinch of salt and enough cold water to cover. Bring to the boil then reduce the heat and simmer gently for 1-1½ hours until the meat is tender.
Shortly before the ribs are cooked, preheat the grill to medium or light a barbecue.
Whisk all the ingredients for the barbecue sauce together in a saucepan. Bring to the boil over a high heat, then reduce the heat and simmer for about 5 minutes until you have a thick sauce.
Remove the ribs from the pan and place in a large baking dish or roasting tray, then coat with half the barbecue sauce. Cook under the hot grill or on the barbecue for 5 minutes on each side and then serve with the rest of the barbecue sauce (reaheat if necessary) and devour!