Cut off the tops of the peppers and remove the seeds. Fill a saucepan with about 2cm depth of water and bring to a light simmer. Place peppers into a steamer basket and steam the peppers for about 10 minutes, until softened. Remove from the pan and place into an ovenproof casserole dish.
Heat oil in a frying pan and cook and stir onion until soft. Add lamb mince and brown. Season with garlic, garam masala, cumin, cloves and cayenne and fry for a few minutes, stirring frequently. Pour in the tomatoes with their juices and simmer for 5 minutes.
Stuff the peppers with the lamb mixture and sprinkle with cheese.
Bake for about 15 minutes in the preheated oven, until cheese is melted and lightly browned.