Sauté eggplant, potato, celery, and onion in butter in a large Dutch oven until tender. Stir in thyme, basil, and curry powder; let cool. Transfer vegetable mixture to container of an electric blender; process until smooth.
Return pureed mixture to Dutch oven. Stir in chicken broth; bring to a boil. Reduce heat; cover and simmer 45 minutes. Remove from heat; add warm whipping cream, stirring well. Stir in salt and pepper. Ladle into individual soup bowls; serve immediately.