Prep the ingredients: Dice the onion, carrots, celery, zucchini, and bell pepper. Chop the kale or spinach and cut the cauliflower into small florets.
Shred or dice the cooked chicken.
Soften the aromatics: Heat 1 tablespoon olive oil in a large pot over medium heat. Add onion, carrots, and celery with a pinch of salt. Cook 5–6 minutes, stirring occasionally, until the onion is translucent.
Add garlic and spices: Stir in the minced garlic, thyme, and oregano.
Cook 30 seconds, just until fragrant—don’t let the garlic brown.
Build the base: Add zucchini, bell pepper, and cauliflower. Stir to coat with the aromatics and herbs. Cook 2–3 minutes to start softening the vegetables.
Pour in the broth: Add low-sodium chicken broth (about 8 cups) and the bay leaf.
Bring to a gentle boil, then reduce to a simmer.
Simmer until tender: Let the soup simmer 12–15 minutes, or until the cauliflower and carrots are tender but not mushy.
Add the chicken and greens: Stir in the shredded chicken and kale or spinach. Simmer 3–5 minutes more, until the greens wilt and the chicken is heated through.
Finish and season: Turn off the heat. Stir in lemon zest and 1–2 tablespoons lemon juice.
Add chopped parsley. Taste and season with salt and black pepper. If you like a tiny kick, add a pinch of red pepper flakes.
Serve: Ladle into bowls and enjoy as is, or add a squeeze more lemon on top for extra brightness.