Preheat and prep: Heat your oven to 350°F (175°C). Lightly grease a 9-inch pie dish.
Mix the crust: In a bowl, combine almond flour, coconut flour, sweetener, cinnamon, and salt. Stir in melted butter, egg, and vanilla until the mixture forms a soft dough that holds together when pressed.
Press and par-bake: Press the dough evenly into the pie dish across the bottom and up the sides.
Prick the bottom a few times with a fork. Bake for 10–12 minutes until just starting to set and lightly golden at the edges. Set aside to cool slightly.
Make the filling: In a large bowl, whisk pumpkin puree, sweetener, heavy cream, almond milk, eggs, spices, salt, and vanilla.
Whisk until smooth and well combined. The mixture should be pourable and silky.
Fill the crust: Pour the filling into the warm crust. Tap the dish gently on the counter to release any bubbles.
Bake: Reduce oven temperature to 325°F (165°C).
Bake for 45–60 minutes, or until the edges are set and the center still has a gentle jiggle. If the crust starts to brown too fast, tent the edges with foil.
Cool completely: Remove from the oven and cool on a rack for at least 2 hours. The pie will finish setting as it cools.
Chill before slicing: For the cleanest slices and best texture, refrigerate at least 3–4 hours, or overnight.
Serve: Slice and top with lightly sweetened whipped cream and a pinch of cinnamon if you like.