Prepare spice rub

The day before you cook ribs, make spice rub. In a medium bowl, mix brown sugar, paprika, cayenne pepper, cumin, salt and pepper together. Place ribs on two large baking trays and rub all over with spice mixture. Cover and refrigerate for at least four hours and up to 24 hours.

Make barbecue sauce

In a large saucepan, heat oil over medium heat. Add onion and cook, stirring often, for about five minutes or until tender. Stir in garlic and cook for about three minutes or until garlic is tender.

Stir in stock, vinegar, tomato sauce, honey, Worcestershire sauce, mustard, paprika, cayenne, 1 tsp. sea salt and 1/2 tsp. pepper. Bring sauce to a simmer over high heat. Reduce heat to medium-low and simmer uncovered, stirring often to prevent scorching, for about 30 minutes, or until sauce reduces and thickens slightly. Remove from heat.

Prepare barbecue for low cooking over indirect heat.

For a gas barbecue place foil pan over one or two unlit burners and half-fill pan with water. Turn on remaining burner(s) and heat grill to 150C. Spread one cup of drained woodchips on a piece of heavy-duty aluminium foil. Place foil directly on lit burner and wait until chips are smoking before you add ribs to grill.

For a charcoal barbecue place foil pan on charcoal grate on one side of grill and half-fill pan with water. Build a charcoal fire on other side and let it burn until coals are covered with white ash and you can hold your hand just above cooking grate for four to five seconds. (To check temperature more accurately, cover grill and drop a long-stemmed metal candy thermometer through the top vent; it should register about 150C.) Sprinkle one cup of drained woodchips over coals.

Combine apple cider vinegar and ¾ cup water in spray bottle. Place ribs on cooking grate over water-filled pan.

Cook with lid closed, turning ribs over and spraying them every 45 minutes or so with vinegar mixture, adding another cup of drained woodchips at same intervals, for about three hours, or until meat is just tender. If using a charcoal barbecue, you will need to add 12 ignited charcoal briquettes (or equivalent in hardwood charcoal) to fire along with woodchips every 45 minutes to maintain temperature. Note: For either barbecue, do not add more wood chips after 1½ hour point, as too much smoke will give the ribs a bitter flavour.

Once ribs are tender, brush lightly with barbecue sauce every few minutes or so, allowing sauce to set before applying next coat. Continue brushing ribs with sauce, turning occasionally, for about 30 minutes, or until meat has shrunk from the ends of bones. Transfer ribs to a carving board and let rest for five minutes.

To serve cut racks into individual ribs using a large sharp knife. Arrange ribs on a platter and serve with remaining sauce on side.

Note: Barbecue sauce can be made up to two weeks ahead, cooled, covered, and refrigerated; reheat before using.