Heat butter in a Dutch oven over medium heat; add carrots, potato, onion, celery, chicken broth, and ginger. Cover and cook, stirring occasionally, until vegetables are tender, about 30 minutes. Uncover and cool for 15 minutes.
Transfer soup in batches to a food processor; blend until smooth. Return soup to the Dutch oven; stir in cream. Add curry powder, salt, and black pepper; cook over low heat until heated through, about 10 minutes.
