Prepare the crust: In a bowl, combine the almond meal and melted butter. Stir until well mixed. Press the mixture into the bottom (and sides, if desired) of a 20 cm (8-inch) springform pan. Set aside.
Make the filling: In a separate bowl, whip the heavy cream until stiff peaks form. Set aside. In another bowl, combine the cream cheese, sour cream, sweetener, lemon juice, and vanilla extract. Mix until smooth. Gently fold in the whipped cream.
Assemble the cheesecake: Pour the cheesecake filling over the prepared crust. Smooth the top with a spatula.
Chill: Cover the cheesecake and refrigerate for 4 hours or overnight to allow it to set.
Optional toppings: Whip the remaining heavy cream, sweetener, and vanilla extract to stiff peaks. Garnish the cheesecake with whipped cream, berries, or your choice of keto-friendly toppings.