Kielbasa soup

About 25 years ago I found a recipe similar to this in The Detroit Free Press and have been making variations of it ever since. This one calls for cabbage but other greens like spinach and kale work well too.  What makes this soup different is the addition of vinegar at the end of the cooking process. I usually use more than the 1/4 cup called for, but adjust to your own taste.

2 Tbl. olive oil
1 large onion, chopped
2 carrots , sliced into rounds
2 stalks celery chopped
2 cloves garlic, minced
1 to 1 1/2 lbs. kielbasa or smoked sausage, sliced into thin rounds
4 -5 medium potatoes, peeled and chopped
8 to 10 cups chicken broth or stock
5 cups chopped cabbage
2 tsp. black pepper
1/2 cup chopped parsley
1/4 cup red wine vinegar ( or white)
salt to taste

In a large soup pot saute the onion, celery, carrot and garlic until soft and fragrant.  Add the sausage and saute the mixture about 5 minutes more. Stir in the potatoes and broth, bring to a boil, and simmer about 15 minutes until the potatoes are cooked.  Add the chopped cabbage, parsley and pepper and continue to simmer about 10 more minutes. Season with salt and the vinegar.

This makes about 6 quarts of soup