Preheat the oven to 400℉ (204℃).

Using a large chef's knife, slice the spaghetti squash in half lengthwise through the stem and scoop the seeds out with a large spoon. Place the squash cut side down in a large baking dish or roasting pan. Add a little water to the pan (just to cover the bottom) or cover the pan with foil. Roast the squash for 30 to 45 minutes or until it is tender. When the squash is fully cooked, the flesh will pierce easily and when scraped with a fork, will separate into spaghetti-like strands.  After the squash has cooled, puree in a blender or food processor until smooth. Set aside 2 3/4 cups of pureed squash to use for the filling. 

Preheat oven to 350℉ (176℃ ) and prepare pie filling.

Add all pie ingredients to a blender and blend until smooth, scraping down sides as needed. Taste and adjust seasonings as needed. Pour filling into pie crust and bake for 58-65 minutes. The crust should be light golden brown and the filling will still be just a bit jiggly and have some cracks on the top. Remove from oven and let cool completely before loosely covering and transferring to the refrigerator to fully set for 4-6 hours, preferably overnight.

Slice and serve with your whipped topping of choice.