Mix the dry rub ingredients with ½ tsp flaky sea salt, then massage into the meat. Marinate for at least 1 hr, or ideally up to 1 day in the fridge.
To make the sauce, heat the oil in a small saucepan and soften the garlic for 1 min. Stir in the rest of the ingredients, plus 2 tbsp water and simmer for a few secs until the sugar melts. Season with salt and set aside.
Heat oven to 160C/140C fan/gas 3. Put the ribs in a roasting tin in 1 fairly snug layer. Pour in 100ml hot water, cover the dish tightly with foil and bake for 2 hrs until the meat pulls easily from the bones. Drain off any fat. The ribs can be cooled and kept in the fridge for up to 2 days.
For the final stage of cooking, get the barbecue ready and wait until the coals are glowing white and grey. Cook the ribs for 4-5 mins on each side until dark golden and hot through – use tongs to turn them carefully. Brush with some of the chipotle sauce and give the ribs 1 min more to char here and there. Serve on a platter with the rest of the sauce for spooning, lime wedges, plus a big bowl of Smoky corn & avocado salsa (see related recipes, right).