Dice the onion, carrots, and celery. Mince the garlic. Cut the cauliflower into florets and chop the kale.

In a large pot, heat over medium heat. Add the Italian sausage and cook until browned, breaking it up with a spoon, about 5-7 minutes.

Add the diced onion, carrots, celery, and minced garlic to the pot. Sauté until the vegetables are softened, about 5 minutes.

Stir in the cauliflower florets, chicken broth, water, thyme, bay leaf, salt, and pepper. Bring to a boil.

Reduce heat to low, cover, and let simmer for about 20 minutes, or until the cauliflower is tender.

Stir in the chopped kale and cook for an additional 5 minutes until wilted. Adjust seasoning if necessary.

Remove the bay leaf and ladle the soup into bowls. Serve hot.