Vegetable Soup

Vegetable Soup
1/2 large onion, chopped
2 Tbls olive oil
2 stalks celery, chopped
3/4 pd. fresh green beans, ends trimmed, and broken into pieces
4 large carrots, peeled and chopped
2 cups red cabbage, shredded
1 cup frozen baby peas
2/3 of 29 oz can tomato puree
6 oz bag baby spinach
Italian seasoning
salt
pepper
fresh parmesan, for grating on top

Heat oil in a Dutch oven over medium-high heat. Add onion and saute until tender. Add celery and carrots. Cook for 1-2 minutes. Add green beans. Cover vegetables with water. Add cabbage and peas. Add more water, to make sure the vegetables are completely covered. Stir in tomato puree and seasonings. Simmer for 1 1/2 hours. Right before serving, stir in spinach. Ladle into bowls and grate parmesan on top and add more seasoning, if necessary.