In a large saucepan bring water and 2 teaspoon salt to a boil over high heat. Add macaroni all at once, stirring to prevent sticking. Cook as package directs until pasta is tender but still slightly firm. Drain. Heat 2 tablespoons butter in a 10-inch skillet; add chopped onion and saute slowly until it begins to turn golden brown. Add meat and break up lumps with a wooden spoon, cooking until it has lost its red color. Add tomato sauce, I teaspoon salt, garlic, and 1 teaspoon ground cinnamon. Simmer 20 minutes. Meanwhile, grease a 13 x 9 x 2 - inch baking dish; add half of the macaroni. Top with meat sauce, spreading it evenly over macaroni. Add remaining macaroni. Preheat oven to 350. In medium saucepan melt remaining 3 tablespoons of butter and stir in flour. Remove from heat; slowly stir in milk. Beat with a wire whisk until smooth; simmer about 5 minutes until thickened. Remove from heat and cool slightly. In a medium sized bowl beat eggs slightly with a wire whisk. Slowly add half of the hot cream sauce, beating constantly. Return mixture to remaining sauce in pan and beat until smooth. Season to taste with salt, pepper, and nutmeg. Sprinkle top of macaroni with remaining cinnamon and pour sauce over all. Tap pan hard on counter top so that sauce goes to the bottom. Bake 40 minutes or until custard is firm. Let stand at room temperature for 10 minutes before serving. Makes 6 to 8 servings.