In a large pot, heat the olive oil over medium heat. Add the diced onion, garlic, carrots, and celery. Sauté for about 5 minutes until the vegetables are softened.

Add the diced potatoes and cook for another 5 minutes, stirring occasionally.

Pour in the vegetable broth and bring the mixture to a boil. Reduce heat and simmer for 20 minutes, or until the potatoes are tender.

Stir in the heavy cream, thyme, basil, salt, and pepper. Cook for an additional 5 minutes.

Using a blender, carefully puree the soup until smooth. You can blend it in batches if necessary.

Serve hot, garnished with fresh parsley.