Cook macaroni according to package directions; drain well, and set aside.
Brown beef in a large skillet, stirring to crumble. Drain off drippings; discard. Add 1/4 cup butter, onion, and green pepper; cook, stirring often, until vegetables are tender. Add salt, pepper, and oregano.
Combine tomato paste and water; add to meat mixture. Simmer, stirring occasionally, until thickened. Remove from heat. Stir in 1/2 cup cheese and cinnamon. Beat 1 egg white (at room temperature) until soft peaks form. Add to meat mixture, blending well; set aside.
Scald milk in a large saucepan; set aside. Melt 1/2 cup butter in a heavy saucepan over low heat; add flour, stirring until smooth. Cook 1 minute, stirring constantly. Gradually add milk, stirring constantly, until thickened and bubbly. Remove from heat. Add 3/4 cup cheese; stir until cheese melts.
Combine 3 egg yolks and 3 whole eggs in a large mixing bowl; beat well. Gradually stir in hot cream sauce mixture, stirring constantly; set aside.
Spread two-thirds of macaroni in a greased 12- x 8- x 2- inch baking dish. Add remaining egg white; mix thoroughly. Sprinkle 1/4 cup cheese on top of macaroni. Melt remaining 1/4 cup butter; pour over cheese. Spread meat mixture evenly over surface. Cover with remaining macaroni; sprinkle with remaining 1/4 cup cheese. Pour cream sauce over top. Bake at 350° for 1 hour.