In a large saucepan combine onion, water, and bouillon granules. Bring to boiling. Reduce heat and simmer, covered, about 10 minutes or until onion is very tender; cool slightly. Do not drain.
Transfer mixture to a blender container or food processor bowl. Add pumpkin. Cover and blend or process until smooth. Return pumpkin mixture to saucepan. Stir in half-and-half or light cream, pear nectar, ginger, and white pepper. Cook and stir until heated through.
Ladle into soup bowls. If desired, garnish each serving with pear slices. Makes 6 servings.