Romanian Meatball sour soup /Ciorba de perisoare

This is a very tasty traditional Romanian sour soup with meatballs and vegetable.

Ingredients:

Broth:
500gr beef bones for soup
1 medium onion, chopped finely 
2 medium carrots, chopped finely,
1/2 parsley root chooped finely (optional)
1/2 cup of cellery root chooped finely
1/4 cup of red and green peper chopped finely (optional)
1/3 cup of fresh tomato chopped
 2 Tbsp oil, for sautéing,
2-3 Liters water,
optional - tomato juice (or sauce, depending on desired consistency), about 2 cups or to taste  
Romanian (or Polish) "bors" (or lemon juice) to taste
1 teaspoon of Vegeta
salt and peper to taste
green parsley leafs

Meatballs:

1/2 Kg ground beef meat,

1/3 cup rice,

1 egg,

1/4 chopped onion

1 tablespoon parsley,

1 teaspoon flour 

1 teaspoon Vegeta,

salt, pepper to taste.

Preparation:

To make the meatballs, mix together all the ingredients. Then take a little of this mixture at a time in slightly damp hands (so as not to be sticky) and make walnut-sized little balls.

For the broth boil the beef bones in the cold water when meat half way done, start separately in a pot to sautee the onion slightly, then add the carrots , cellery root, and rest of the vegetables, and cook at medium low for 5 minutes. Add the  black pepper and add the sautee vegetable to the beef broth, leave to boil for 15 minutes, then add the meatballs.

Boil until meat balls are tender and well cooked, and towards the end add the tomato juice or sauce and the "bors" (the "bors" is not supposed to boil more than a few minutes). Make sure that the meatballs are cooked through, top with more fresh chopped parsley and serve with a tablespoon sour cream in the plate.