Preheat oven to 400 degrees F. Line a rimmed baking sheet with aluminum foil.
Place squash on baking sheet and bake 60 to 70 minutes, or until a knife can be inserted into squash. Remove from oven and let cool slightly, 15 to 20 minutes.
Cut the squash in half lengthwise; scoop out the seeds and discard. Using a spoon, remove the flesh and place in a casserole dish.
Add the remaining ingredients and mix well. Serve immediately or refrigerate and reheat at a later time.