In a large pot or dutch oven, heat oil and butter over medium heat. Sautee the diced carrots, parsnips and onions for 10 minutes. Stir frequently to prevent browning. Season vegetables lightly with salt and pepper.
Lower heat and add vegetable broth and water to the pot. Stir in garlic powder, turmeric, ground ginger, and bay leaf. Add in the bouquet garni of fresh herbs. Cover and let simmer for at least 30 minutes or until the vegetables are fork-tender.
Once the vegetables are tender, remove and discard the bay leaf and bouquet garni.
Using a food processor or blender, puree together the soup until smooth- This may need to be done in batches.
Return the pureed soup to the pot and stir in milk. If needed, season the soup with additional salt and pepper.
Serve soup warm and garnish with chopped parsley and pepitas.