Preheat your oven to 350 degrees Fahrenheit.
Trim any excess fat from your lamb pieces. Season the lamb evenly with the 1 teaspoon salt and 1 teaspoon pepper.
Heat vegetable oil in a deep frying pan so that you can brown the lamb pieces. Add enough oil so that it is approximately 1/4 inch deep in pan.
Cook lamb pieces until all sides are nicely browned, approximately 4– 5 minutes per side. You are not fully cooking the lamb; you simply want it browned on all sides. You may need to do this in batches depending on the size of your pan.
Once all of the lamb is browned, transfer the pieces to your roasting pan. We used a round roasting pan which was approximately 15 inches in diameter.
To the pan add 1/4 cup olive oil, 2 ¾ cups tomato sauce, and 7 ½ cups boiling water. Sprinkle with 1 teaspoon of cinnamon and add the cloves if you are using them.
Cover the pan tightly with aluminium foil and place it in the bottom rack of your oven for 1 hour 30 minutes. Check your lamb for doneness by inserting a fork into one of the pieces; if you can easily insert your fork and separate out a small pieces of the lamb, it is ready.
Carefully remove the pan from the oven, and uncover it. Increase your oven temperature to 400 degrees Fahrenheit. Add the uncooked orzo. Stir carefully. Return pan to oven, uncovered.
After 10 minutes, carefully stir the orzo in the pan as it will have a tendency to stick to the bottom. We found that the easiest way to do this was with a spatula (easy to scrape up the orzo pieces stuck to the bottom of the pan), using an oven mitt, while the pan was still in the oven. Alternatively you can place the pan onto the stove top, mix, and then return to the oven. Repeat this every 5 minutes for the next 15 minutes.
Note: The total cooking time after adding the orzo should be 25 minutes.
If at any point after adding the orzo, your meal appears too dry, you can add a bit of boiling water and mix well.
Remove from oven, let cool slightly and serve.
Enjoy!