Preparation

1. Pre-heat oven to 350F
2. Place squash cut side down on a rimmed baking sheet or 9 x 13" pan. Add 2 cups water and roast for about 45 minutes until squash is tender. Thirty minutes into baking, add apples. Remove from oven, drain off any remaining water, and let cool
3. Meanwhile in a heavy 12-quart pot over moderate heat, add oil. Add onions, garlic, celery, salt and pepper. saute onions until they are soft, about 10 minutes. Add apple cider and bring to a boil. Reduce heat and simmer uncovered until liquid is reduced by half
4. When squash is cool enough to handle, scoop out the flesh and add to the pot. Add vegetable broth and apples, raise heat to high, and bring to a boil. Reduce heat and simmer uncovered until all vegetables are tender, about 25 minutes
5. Working in batches, puree soup in blender until very smooth, and then return to pot. Set over moderate heat and return to simmer. Check seasoning of soup by tasting and adding a little salt or pepper if needed
6. To serve, ladle soup into bowls and sprinkle with toasted pumpkin seeds, if desired. Serve immediately.