1. Heat the butter and oil in a 6-quart saucepot over medium heat. Add the squash, apples, onion, sage, salt and black pepper and cook until the vegetables are almost tender.
2. Stir the broth in the saucepot. Heat to a boil. Reduce the heat to low and cook for 10 minutes or until the squash is tender.
3. Using an immersion blender, puree the squash mixture. Serve the soup with the crackers, if desired.