Heat olive oil in a soup pot over medium heat. Cook chopped onion for 3–4 minutes, then add minced garlic and cook for 30 seconds.
Add diced carrots and sliced celery. Cook for 5 minutes until slightly softened.
Stir in zucchini, green beans, and diced tomatoes. Cook for 3–4 minutes.
Pour in vegetable broth and season with salt, pepper, Italian herbs, and paprika. Bring to a gentle boil, then simmer for 15 minutes.
Stir in spinach or kale and cook 2–3 minutes until wilted. Add parsley and optional lemon juice.
Taste and adjust seasoning. Rest for 2 minutes before serving.