In a large Dutch oven or heavy-bottom pot, heat the olive oil over medium-high heat. Add the beef cubes and sear until browned on all sides, approximately 5-7 minutes. Remove the beef and set aside.
In the same pot, add the chopped onion and garlic. Sauté until the onion becomes translucent, about 3-4 minutes.
Stir in the diced tomatoes, oregano, ground cinnamon, salt, and pepper. Cook for another 2-3 minutes, allowing the flavors to meld.
Return the beef to the pot and pour in the beef broth. Bring the mixture to a simmer, then cover the pot and let it cook on low heat for about 1 hour, or until the beef is tender.
Once the beef is tender, add the orzo pasta directly into the pot. Stir well and adjust the seasoning if needed. Cover and cook for an additional 10-12 minutes, or until the orzo is cooked al dente and has absorbed some of the liquid.
If the mixture appears too thick, add a little more broth or water. Stir well to combine.
Remove from heat and let the dish sit for a couple of minutes. Serve hot, garnished with fresh parsley and a sprinkling of feta cheese if desired.