Preheat and prep: Heat your oven to 350°F (175°C). Lightly grease a 9-inch pie dish.
Mix the crust: In a bowl, whisk almond flour, coconut flour, sweetener, salt, and cinnamon.
Stir in melted butter, egg, and vanilla. Mix until it forms a slightly sticky dough.
Press and par-bake: Press the dough evenly into the pie dish, pushing up the sides. Dock the base with a fork.
Bake 10–12 minutes, until just set and lightly golden. Let it cool 5 minutes.
Make the filling: In a large bowl, whisk pumpkin, eggs, sweetener, heavy cream, spices, vanilla, and salt until smooth. Avoid whipping in too much air.
Assemble: Pour the filling into the warm crust.
Smooth the top with a spatula.
Bake: Bake 45–55 minutes. The edges should be set, and the center should still jiggle slightly. If the crust browns too fast, cover the edges with foil.
Cool and set: Cool on a rack for at least 2 hours.
Then chill 3–4 hours, or overnight, to fully set the custard.
Serve: Slice with a sharp knife. Top with whipped cream and a pinch of nutmeg, if you like.