1. In a small bowl, combine brown sugar and pumpkin pie spice. 2. Next, spoon the mixture into squash halves. 3. Sprinkle with raisins and dot with butter. 4. Wrap each squash half individually in heavy-duty aluminum foil; seal tightly. 5. Pour water into a slow cooker. 6. Place squash, cut-side up, in slow cooker (packets of foil may be stacked). 7. Cover and cook on high setting for 4 hours; until squash is tender. 8. Open foil packets carefully, to allow steam to escape. 9. Cut up into portions, for approximately 4 servings.