1. Marinate the chops in the lime juice, vinegar, chili powder and a pinch of salt while you make the rest of the marinade.
2. Heat 100ml of the oil in a small saucepan and add the gram flour, stirring continuously for a minute or two until the flour forms a smooth sandy paste and you begin to smell a nutty aroma. Transfer the paste to a bowl and leave to cool.
3. Crush the star anise using a pestle and mortar, then tip into a food processor with the chilies, garlic, papaya and the remaining oil and blend to a smooth paste. Mix both pastes over the marinated meat and refrigerate for a minimum of 4 hours.
4. To cook the chops, preheat the oven to fan 180C/conventional 200C/gas 6. Lift the chops out of the marinade and wipe off any excess so the chops are just lightly coated. Heat 1 tbsp oil in a large frying pan and fry the chops in batches for a couple of minutes on each side until browned. Transfer to a roasting tray and roast for 10-20 minutes depending on how pink you like your lamb. Serve the chops with mint sauce.