In a large pot, heat a tablespoon of oil over medium heat. Add the chopped onion, garlic, and celery. Sauté until the onion is translucent, about 5 minutes.

Add the chopped carrots and potato to the pot, stirring to combine.

Pour in the vegetable broth and add the cumin, salt, pepper, and thyme. Bring to a boil, then reduce heat and simmer for about 25 minutes, or until the vegetables are tender.

Remove the pot from heat. Using an immersion blender, blend the soup until smooth. Alternatively, carefully transfer the soup to a blender in batches and blend until smooth.

Stir in the heavy cream and adjust seasoning if necessary. Heat through for a few minutes, then serve hot, garnished with fresh parsley.