Put all the marinade ingredients into a food processor and blend them to a smooth purée.
Place the minced lamb in a mixing bowl, add the marinade and blend thoroughly. Cover and leave to marinate for 1-2 hours, or refrigerate overnight, to allow the flavours to develop. Bring the meat to room temperature before cooking.
Heat the oven to 200°C (400°F, gas mark 6). Spread the meat out evenly in a 25 × 20 cm (10 × 8 in) ovenproof dish and bake it in the top half of the oven for 10 minutes.
Remove the dish from the oven and break the mince down with a fork to chunky pieces, then stir it thoroughly so that it absorbs any cooking juices. Return it to the oven and cook for a further 15-20 minutes, stirring halfway through, until the mince is lightly browned and most of the cooking juices have evaporated. Then give it a final stir so that any remaining juices are absorbed.
Spoon equal portions of lamb on top of each chapatti, then top each with some chopped salad vegetables and a little fromage frais. Serve garnished with a sprinkle of paprika and a few mint leaves.