Vegetable Soup (with or without beef)

1-2 tablespoons olive oil
1 yellow onion, chopped
2 stalks celery, chopped
1 pound lean beef  cut into bite sized pieces (optional)
7 cups broth or water
1 cup red cabbage, roughly chopped
3 carrots, chopped
1 can crushed tomatoes
1 cup frozen corn
1 zucchini, cut in half and thinly sliced
1 yellow squash, cut in half and thinly sliced
3 tablespoons Tamari or Soy sauce
1 tablespoon rice or red wine vinegar
1 teaspoon Sriracha

In a large pot or dutch oven, brown the meat in 1 tablespoon of oil.
Add the onion and celery and sauté for about 2-3 minutes.
Add broth, cabbage, carrots and tomatoes and bring to a boil.
Reduce heat and simmer partially covered until beef is tender, about 30 minutes. Add the zucchini and squash and simmer until tender, about 10 more minutes.
Stir in the corn and serve.