Heat the olive oil in a large pot over medium heat. Add the chopped onion and sauté until it becomes translucent, about 5 minutes.
Add the peeled and diced potatoes to the pot and cook for another 5 minutes.
Stir in the tomato paste and dried oregano, allowing them to cook for about a minute.
Add the chopped eggplant, zucchini, bell pepper, chicken broth (or water), and canned chopped tomatoes to the pot. Stir well to combine all the ingredients.
Bring the soup to a simmer, then reduce the heat to low and let it cook for about 15-20 minutes, or until the vegetables are tender.
Taste the soup and adjust the seasoning if needed, adding more salt or pepper to taste.
Finally, stir in the chopped fresh parsley just before serving to add a burst of fresh flavor to the soup.
Serve the vegetable soup hot, garnished with additional fresh parsley if desired.
