In a large pot, heat the olive oil and butter over medium heat. Add the onion, celery, carrots, garlic, oregano, thyme, and rosemary and cook for 5 minutes, or until the vegetables are softened.
Add the potatoes and chicken stock and bring to a boil. Reduce the heat to low and simmer for 15 minutes, or until the potatoes are tender.
Add the cream and season with salt and pepper, to taste. Simmer for 5 minutes, or until the soup is creamy and thickened.
Serve the soup garnished with parsley, bacon, and chives, if desired.