Preheat oven to 350°. In a large skillet, cook beef and onion over medium heat until meat is no longer pink, 7-9 minutes, breaking into crumbles. Add garlic; cook 1 minute longer. Drain. Stir in water, tomato paste, parsley, salt, mint if desired, cinnamon and pepper. Set aside., For sauce, melt butter in a saucepan over medium heat. Stir in flour until smooth; gradually add milk. Bring to a boil; cook and stir for 2 minutes or until thickened. Remove from the heat. Stir a small amount of hot mixture into eggs; return all to the pan, stirring constantly. Add cheese and salt., Place half of the potato slices in a greased shallow 3-qt. baking dish. Top with half the cheese sauce and all of the meat mixture. Arrange remaining potatoes over meat mixture; top with remaining cheese sauce., Bake, uncovered, until a thermometer reads 160°, about 1 hour. Let stand for 10 minutes before serving.