Place the carrots, onions, and cinnamon stick in a large slow-cooker insert.
Heat the oil in large skillet over medium-high heat until hot. Add the beef, in batches if necessary; cook 5 to 7 minutes or until browned on all sides.
Place the beef on top of the vegetables in the slow cooker. Sprinkle with garlic, salt and pepper; top with tomatoes. Cover and cook on low 8 to 10 hours or until the beef and vegetables are tender.
Gently remove the beef and vegetables with a slotted spoon and wrap in foil to keep warm; discard the cinnamon stick. Add the tomato paste, lemon zest, and oregano to the slow cooker; stir to combine. Cover and cook on low 15 to 20 minutes or until thickened and heated through. Stir the beef and vegetables back into the sauce. Serve in bowls and sprinkle each serving with cheese.