Pierce squash several times with the tip of a sharp knife. Microwave at HIGH 1 minute. Cut squash in half lengthwise; remove seeds and membrane with a spoon. Peel squash, and cut into 1-inch chunks.
. Heat oil in a Dutch oven over medium heat. Add onion and next 3 ingredients; sauté 5 minutes. Add ginger, squash, and apple to pan; sauté 3 minutes. Add broth and cinnamon stick; bring to a boil. Cover, reduce heat, and simmer 30 minutes. Discard cinnamon stick.
. Place half of soup in a blender, and process until smooth. Transfer to a large bowl. Repeat with remaining soup. Return soup to pan. Stir in lemon juice, and cook over low heat 2 minutes or until thoroughly heated, stirring frequently.