Bring a large pot of lightly salted water to a boil. Add macaroni noodles, and cook until tender, about 8 minutes. Drain, and set aside.
Preheat the oven to 350 degrees F (175 degrees C). Cook ground beef and onion in a large skillet over medium-high heat until beef is evenly browned. Remove from heat, and drain grease. Stir in the tomatoes, feta cheese, Parmesan cheese, and cinnamon. Mix in pasta, and transfer to a large baking dish.
In a saucepan over medium heat, mix together the milk and cornstarch until no lumps remain. Add butter, and bring to a boil. Boil for 1 minute, then remove from heat, and pour the sauce over the mixture in the baking dish.
Bake for 1 hour in the preheated oven, until the top is golden brown. Let stand for 10 minutes before serving.