If the meat is not already diced, or the pieces are large, cut it in to roughly bite-sized pieces and season with some salt and pepper. Peel and dice the onion and finely chop the garlic.
Warm half the oil in a Dutch oven and brown the meat on all sides to sear it, working in batches so you don't overcrowd the pan and removing to a plate as they are done.
In the same pan, add the rest of the oil and soften the onions, adding the garlic after a minute. Cook until going translucent but not brown, around 3-5 minutes.
Deglaze the pan with the wine - allow the alcohol to boil off and scrape the bottom to incorporate all the flavor into the sauce.
Add the tomatoes, tomato paste, cinnamon, nutmeg, sugar and stock and add back the meat. Stir to combine and bring to a simmer then cook on low for around 1 hour or until tender, covered (it's also great cooked longer eg 2 hours, to make the meat extra-tender).
Preheat oven to 350F/175C then add the orzo to the pot. Mix it through then bake for approx 25 minutes, uncovered, until orzo is tender and cooked. You can also continue cooking with the orzo on the stovetop - in this case, cook relatively low so that it simmers with the lid partially covering. Stir now and then to avoid the orzo sticking to the bottom and browning/burning.
Serve with grated cheese on top.