Preheat oven to 170C. Chop the onion finely. In a pan add some olive oil, onion and garlic. Cook until the onion softens. Add the meat and cook until brown. Once the meat is browned on all sides, add a bit of warm water to half cover the ingredients and let it boil for 15 minutes.
In an oven-proof pot, put all the ingredients, onion, garlic, beef and its juices, olive oil, grated tomatoes and tomato paste, cinnamon, sugar and a little warm water to cover. Mix ingredients well and cover with foil. It will take an 1 - 1 ½ hour for the meat to soften. Keep checking after the first 50 minutes. Once meat has softened, add the orzo and stir occasionally. Add some water if needed. It should take approximately 15 minutes for orzo to be cooked. When orzo is cooked, serve each portion sprinkling some grated kefalotyri on top.