Stir graham cracker crumbs, melted butter, and sugar in a bowl until the texture of wet sand. Divide evenly among 12 lined muffin cups, pressing firmly with the bottom of a small glass or measuring cup. Freeze while you make the filling.

Beat softened cream cheese in a large bowl until completely smooth and no lumps remain, about 2 minutes. Scrape down the bowl twice during mixing.

Add pumpkin puree, powdered sugar, pumpkin pie spice, and vanilla. Beat on medium speed until fully combined and creamy, about 1 minute.

In a separate bowl, whip cold heavy cream to stiff peaks, about 3-4 minutes. Fold half the whipped cream into the pumpkin mixture to lighten it, then fold in the remaining cream until no streaks remain.

Divide filling evenly among the crusts, smoothing the tops with an offset spatula or spoon. Refrigerate until set, at least 3 hours or overnight. The centers should feel firm to the touch.

Remove from refrigerator 10 minutes before serving. Top with whipped cream and a dusting of cinnamon if desired.