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

Add the diced potatoes and continue to sauté for another 5 minutes.

Pour in the chicken broth and bring to a boil. Reduce heat and let simmer for 20 minutes until the vegetables are tender.

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

Return the blended soup to the pot and stir in the heavy cream, thyme, salt, and pepper. Heat through for an additional 5 minutes.

Serve hot, garnished with fresh parsley and grated Parmesan cheese if desired.