Preheat the oven to 200°C.
Chop the tops off the courgettes and set aside. Using a small knife or a spoon, carefully hollow out the insides of the courgettes. Chop the flesh, and also put aside.
Place the hollowed courgettes in a roasting tin, sprinkle with two tablespoons of olive oil and salt and pepper. Roast for 30 minutes. If using a large squash or marrow cook for 10 minutes more at this stage.
In the meantime, heat the remaining oil in a frying pan. Add the onion and garlic and cook gently for a few minutes to soften. Add the lamb mince and fry until brown, for about five minutes. Add the chopped courgette and cinnamon and cook for another two minutes.
Stir in the rice and pour in the hot stock. Bring back to the boil and then cover and simmer for 10 minutes.
After 10 minutes, take the rice off the heat. It should be tender.
Take the courgettes out of the oven and carefully spoon in the cooked rice mixture. Return to the oven for 10-15 minutes.
Serve immediately with chopped fresh mint or parsley sprinkled over the top.