In a large saucepan, heat oil over medium heat. Add onion; cook and stir until tender. Add garlic; cook 1 minute longer., Stir in squash, broth, salt and pepper; bring to a boil. Reduce heat; simmer, covered, 10-15 minutes or until squash is tender. Puree soup using an immersion blender. Or cool slightly and puree soup in batches in a blender; return to pan. Add cream; cook and stir until heated through. If desired, garnish with additional heavy whipping cream and crispy sage.