Preheat Oven to 350ºF
Cut the top off turban squash (cutting a lid as you would for a jack o’lantern). Remove seeds and pulp.
Place squash, cut side down, on oiled or foil-lined baking sheet. Cover squash with foil. Roast 50 to 60 minutes or until tender.
Scoop out cooked pulp and save squash cavity for serving.
In a saucepan, sauté onions, celery, and carrot in butter until vegetables are starting to soften, add sausage and cook until meat is fully cooked and vegetables are tender.
Drain grease. Stir in brown sugar, breadcrumbs, salt, pepper, and cooked squash.
Spoon mixture into the cavity of turban squash and cover with squash lid. Bake squash with filling at 350ºF for 20 to 25 minutes or until heated through. Serve hot.