Mix almond flour and melted butter. Press into the bottom of a deep dish pie plate.
Bake for 10 min or until slightly golden. Let cool for at least 10 min before adding the filling.
Filling
With an electric mixer mix the cream cheese until fluffy. Add sweetener, lemon extract, and salt. Mix until smooth. Add eggs one at a time, mixing after each addition. Pour over the prepared crust.
Bake at 350 for 20 minutes. Reduce temp to 200. Bake another 20 min or until set. Cool to room temp.
Sour Cream Topping
Mix sour cream and sweetener. Spread over cooled cheesecake.
Refrigerate until cold (at least 3-4 hours). Sprinkle with berries, if desired.