Preheat the oven to 350 F (177 C). Grease a 9 in springform pan (or line the bottom with parchment paper).

Stir the almond flour, melted butter, Xylitol, and vanilla extract in a medium bowl, until well combined. The dough will be slightly crumbly. Press the dough into the bottom of the prepared pan. Bake for about 10-12 minutes, until barely golden. Let cool at least 10 minutes.

Beat the cream cheese and powdered sweetener together at low to medium speed until fluffy. Beat in the eggs, one at a time. Finally, beat in the lemon juice and vanilla extract. (Keep the mixer at low to medium the whole time; too high speed will introduce too many air bubbles, which we don't want.)

Pour the filling into the pan over the crust. Smooth the top with a spatula (use a pastry spatula for a smoother top if you have one).

Bake for about 45-55 minutes, until the center is almost set, but still jiggly.

Remove the cheesecake from the oven. If the edges are stuck to the pan, run a knife around the edge (don't remove the springform edge yet). Cool in the pan on the counter to room temperature, then refrigerate for at least 4 hours (preferably overnight), until completely set.