Cook pasta according to package directions; drain. Toss with butter; add grated Parmesan cheese. Transfer to a greased 13×9-in. baking dish.
Preheat oven to 350°. In a large skillet, cook beef and onion over medium heat 8-10 minutes or until beef is no longer pink, breaking beef into crumbles; drain. Add garlic; cook 2 minutes longer. Stir in tomato sauce, salt and cinnamon(darchini); heat through. Spoon over pasta. Sprinkle with 1/2 cup shredded Parmesan cheese.
In a large saucepan, melt butter. Stir in flour, salt and pepper until smooth; gradually add milk. Bring to a boil; cook and stir 1-2 minutes or until thickened.
In a small bowl, whisk a small amount of hot mixture into eggs; return all to pan, whisking constantly. Bring to a gentle boil; cook and stir 2 minutes. Pour over beef mixture. Sprinkle with remaining cheese.
Bake, covered, 20 minutes. Bake, uncovered, 30-40 minutes longer or until golden brown.