Add one tablespoon of vegetable oil to a 12-inch skillet over medium heat and cook onion until ten
der
Increase heat to medium-high
Add ground sirloin and 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
Bring to a boil
Reduce heat to low and simmer for 5 minutes
Meanwhile, cook macaroni until al dente, drain and return to pan
Preheat oven to 350?F
To prepare sauce, add 2 tablespoons of vegetable oil to a 3-quart saucepan over medium heat and stir in flour, nutmeg, and 1 teaspoon salt, until blended
Cook 1 minute
Gradually stir in milk and cook, stirring constantly, until mixture boils and thickens for about 10 minutes
Remove saucepan from heat
In small bowl, beat eggs slightly
Into eggs, beat small amount of the hot milk mixture
Slowly pour egg mixture back into milk mixture, stirring constantly until blended
Stir in meat mixture and 1/4 cup Parmesan into macaroni in pan
Spoon into deep 4-quart casserole
Carefully pour sauce over macaroni mixture
In small bowl, mix bread crumbs with 1/4 cup Parmesan cheese, then sprinkle over sauce
Bake, uncovered, 40 minutes or until hot and custard is set
