The trick to preparing this soup quickly is to cut the vegetables into small pieces and as thinly as possible. Dont be intimidated by the unusual shape and tough skin of butternut squash. It peels easily with a swivel peeler or sharp serrated knife. If unavailable, substitute peeled sweet potatoes.
In small saucepan, bring 3 cups broth to a boil over high heat.
Meanwhile, in large, heavy saucepan, heat oil over medium heat. Add garlic, celery, onion, carrot, curry powder, ginger and pinch of salt and cook, stirring often, 5 minutes. Increase heat to high and stir in boiling broth, squash and 1/2 teaspoon salt. Bring to a boil, cover, reduce heat to medium and cook 10 minutes.
Uncover saucepan and stir well with wooden spoon until squash breaks down easily. Stir in maple syrup and vinegar. Remove from heat.
Transfer mixture to blender or food processor in batches and carefully blend until smooth. Return to saucepan and warm through, adding as much remaining 2 cups broth as needed. Serve hot.