Pound half the garlic with the salt in a mortar with a pestle, then mix through all the remaining dry ingredients for the rub. Rub this mixture evenly into the ribs on both sides and leave to marinate while preparing the sauce.

Preheat oven to 150°C. In a saucepan, heat oil on medium and sauté the onion with the pinch of salt and the rest of the garlic until starting to turn golden. Add remaining ingredients and bring to a simmer. Reduce for about 5 minutes. Process with a stick blender, then baste ribs in sauce so it is covered and reduce the rest for the glaze (you should be reducing more than half the amount). Wrap completely in foil.

Place the foil-wrapped ribs on a baking tray and cook for about 1 1/2 hours, until the meat is tender. Continue to reduce the rest of the sauce on the stove top until it becomes a sticky glaze.

Preheat the barbecue on a medium heat. Char-grill ribs, turning and basting with the glaze, until charred and sticky, about 8-10 minutes. Slice and serve on a platter with some fresh lime.