1. To make the smoky rub, combine the chilli powder, smoked paprika, mild paprika, oregano, onion powder and salt in a small pot. Spread the mixture all over the ribs and set aside for 15 minutes to marinate.
2. Preheat the oven to 1600C/3250F/Gas Mark 3 and line a roasting tin with foil. Put a rack in the roasting tin. Place the ribs on the shelf and roast for 1-1,2 hours, or until cooked through and the meat is tender.
3. Transfer the ribs from the oven, cut into serving portions and serve with mashed potato and spring greens, if desired.