Preheat oven to 350°F (175°C).

In a large bowl, combine ground beef, bread crumbs, chopped onion, salt, pepper, and 1/2 cup of tomato sauce.

Mix thoroughly until well combined.

Press the meat mixture into a 9x5x3 inch loaf pan.

In a separate bowl, combine the remaining 1 cup tomato sauce, water, mustard, vinegar, and brown sugar.

Blend the sauce ingredients well.

Pour half of the sauce mixture over the meatloaf in the pan.

Bake in the preheated oven for 1 hour.

Remove the meatloaf from the oven.

Carefully unmold the loaf from the pan and place it on top of hot cooked noodles.

Heat the remaining sauce in a saucepan until warm.

Spoon the heated sauce over the meatloaf.

Garnish with fresh parsley before serving.