Heat the Pot: In a large soup pot, heat olive oil over medium heat.
Saute Aromatics: Add chopped onion and garlic. Saute until translucent, about 3 minutes.
Add Veggies: Stir in celery, bell pepper, zucchini, and cabbage. Cook for 5 minutes, stirring occasionally.
Pour Broth: Add chicken or veggie broth, oregano, paprika, pepper, and red pepper flakes. Bring to a boil.
Simmer: Reduce heat and simmer for 20–25 minutes, until vegetables are tender.
Finish: Stir in lemon juice if using. Adjust salt and pepper to taste.
Rest: Let the soup rest for 5 minutes before serving.
Serve: Ladle into bowls, garnish with fresh parsley, and enjoy warm.