Heat olive oil in a large pot over medium heat. Sauté onion, garlic, carrots, and celery until softened and fragrant.
Add diced potatoes, thyme, rosemary, and bay leaf. Cook for 2–3 minutes, stirring occasionally.
Pour in the broth and bring to a simmer. Cook for about 20 minutes, until potatoes are tender.
Add zucchini and kale (or spinach) and cook 5–7 minutes until greens are wilted and tender.
Stir in lemon juice, and season with salt and black pepper. Remove bay leaf.
Serve hot, garnished with chopped parsley and a sprinkle of Parmesan cheese.
Serving and Storage Tips:
