In a large bowl, mix together the almond flour, sweetener, cinnamon, and melted butter until completely combined. Press the cheesecake crust into the bottom of the tart or springform pan. Place the assembled crust in the refrigerator.
In a large mixing bowl, beat the cream cheese and 2/3 cup powdered sweetener with a hand mixer until creamy.
Add the sour cream, lemon juice, and almond extract and mix until combined. Set aside.
In another mixing bowl, whip the remaining powdered sweetener with the heavy cream for 1 minute, or until stiff peaks form.
Fold the heavy whipped cream into the cream cheese mixture until combined.
Transfer the cheesecake filling to the tart pan and spread evenly with a silicone spatula. Refrigerate for 4 hours.