Preheat oven to 375F. In a skillet, heat oil. Add onion and garlic and cook until soft. Add beef and stir until browned. Stir in stock, tomato paste, cinnamon, mint, salt and pepper. Simmer 10 - 15 minutes or until sauce is reduced. Meanwhile, in a pan of boiling water, cook macaroni 8 minutes or until tender. Drain, rinse with cold water and set aside. Ina a saucepan, melt butter. Stir in flour and cook 1 minute. Gradually stir in milk and yogurt and simmer 5 minutes. Stir in half the cheese. Season with salt and pepper. Mix macaroni int cheese sauce. Spread half the macaroni mixture over bottom of a large gratin or souffle dish. Cover with meat sauce, then top with remaining macaroni. Sprinkle remaining cheese over top. Bake 45 minutes or until browned.