6 cups beef, or vegetable broth
2 cups coarsely chopped green cabbage
1-1/2 cups zucchini, 1/2" thick slices
1 cup vertically sliced onion
1/2 cup sliced celery, 1/2" thick
2 large carrots, halved lengthwise then cut into 1" pieces
2 large garlic cloves, crushed
1/8 cup chopped cilantro
1/4 teaspoon red pepper flakes