Preheat oven to 350°F (175°C). Mix almond flour, granulated sweetener, and salt. Cut in cold butter until crumbly, then press firmly into a 9-inch pie dish. Prick the bottom with a fork.

Line crust with parchment and pie weights. Bake 10 minutes, remove weights, then bake 5 to 7 minutes more until lightly golden.

Whisk eggs until frothy, then stir in pumpkin, heavy cream, powdered sweetener, pumpkin pie spice, and vanilla until smooth.

Pour filling into the warm crust and bake 40 to 50 minutes, until edges are set and center still jiggles slightly. Shield crust edges if they brown too fast.

Cool completely on a wire rack, then refrigerate at least 2 hours. Slice and serve with whipped cream.