Line the base of a 9” springform pan with parchment paper. Place the open exterior ring around the base and close it so the parchment is sealed in the ring. Trim the excess from around the outside.
In a food processor, combine all crust ingredients and blitz 2-3 times until crumbs are all moistened.
Press the crumbs into the springform pan and up the sides about ¼-inch in thickness. Press the mixture along the base, thinning out the corners. Freeze the crust while you prepare the filling.
In a large bowl, beat the softened cream cheese with a handheld electric mixer on med-high speed until light and fluffy. Add ½ cup sugar, pumpkin puree, salt and cinnamon. Whip until smooth and there are no chunks of cream cheese. Beat on low until smooth.
In a separate bowl, beat the heavy cream to soft peaks on medium speed. Add remaining ¼ cup granulated sugar and beat to stiff peaks.
Fold whipped cream into cheese and pumpkin mixture gently so that you deflate as little of the air as possible.
Remove the crust from the freezer. Scrape the pumpkin mixture into the crust and level.
Cover with plastic wrap and refrigerate for at least 8 hours or overnight to set. Remove from the springform pan and serve with whipped cream, if desired.