Melt butter in a large pot over medium heat until foaming. Sauté onion until soft and translucent, about 3-4 minutes.

Add chicken broth, carrots, potatoes, herbes de Provence, thyme, and bay leaf to the pot. Season with salt and pepper. Bring to a boil, then reduce heat to low and simmer until vegetables are tender, approximately 30 minutes.

Carefully transfer the soup to a blender, filling only halfway to prevent overflow. Cover with a lid and a kitchen towel for safety, and blend starting with quick pulses, then continuously until smooth. Work in batches if necessary.

Serve the pureed soup into bowls, drizzle with heavy cream, and garnish with a sprig of parsley. DEVOUR!