In a 12-inch skillet over medium heat, in 1 Tablespoon oil cook onion until tender. Increase heat to medium-high and add ground beef, cook stirring occasionally, until all pan juices evaporate and meat is browned. Add tomatoes with their liquid, sugar, cinnamon and 3/4 teaspoon salt, stirring to break up tomatoes, over high heat until boiling. Reduce heat to low, simmer 5 minutes. In saucepan, prepare elbow macaroni as label directs, using 2 teaspoons salt in water. Drain macaroni, return to pot. Meanwhile preheat oven to 350 degrees. Prepare sauce: In a 3 quart saucepan over medium heat, into 2 Tablespoons hot oil stir flour, nutmeg and 1 teaspoon salt, until blended: cook 1 minute. Gradually stir in milk and cook, stirring constantly, until mixture boils and thickens, about 10 minutes. Remove saucepan from heat. In small bowl, beat eggs slightly. Into eggs, beat small amount of hot mixture. Slowly pour egg mixture back into milk mixture, stirring constantly until blended. Stir meat mixture and 1/4 cup Parmesan cheese into macaroni in saucepan. Spoon into deep 4 quart casserole. Carefully pour sauce over macaroni mixture. In small bowl mix bread crumbs with 1/4 cup Parmesan cheese; sprinkle over sauce. Bake uncovered 40 minutes or until hot and custard is set. Let stand for 10 minutes for easier serving.