Sauté Aromatics: In a large pot or Dutch oven, heat the olive oil over medium heat. Add the chopped onion, carrots, and celery. Cook, stirring occasionally, for 5-7 minutes until they begin to soften. Add the minced garlic and cook for 1 more minute until fragrant.
Add Veggies & Liquid: Add the chopped cabbage, bell pepper, zucchini, and the can of diced tomatoes (with their juices) to the pot. Pour in the vegetable broth.
Season & Simmer: Add the dried oregano, bay leaf, salt, and pepper. Stir everything together. Increase the heat to bring the soup to a boil, then reduce the heat to low, cover, and let it simmer for 20-30 minutes, or until all vegetables are tender.
Finish: Remove the bay leaf. Stir in the optional coconut aminos/tamari and the fresh parsley.
Serve: Taste the soup and adjust seasoning with additional salt and pepper if needed. Ladle into bowls and serve hot.