1. Heat oven to 400°F.
2. Cut squash in half and remove the seeds.
3. Rub the cut flesh with salt and place flesh side down in a baking dish and bake for about 35 minutes.
4. While the squash is baking, sauté onion in butter until clear and add chopped broccoli florets, mushrooms and celery.
5. Sauté about 4 minutes.
6. Stir in walnuts and fresh basil, then sprinkle with brown sugar and soy sauce, adjust seasoning to taste. Toss to mix well.
7. Check baking squash with a fork to see if it glides through the flesh.
8. Stuff with vegetable mixture, top with equal amounts of grated cheese and return to oven for about 5 minutes.