Preheat oven to 180°C and line a 9 inch spring form baking pan.
Melt butter.
Mix in almond flour and Erythritol.
Press into baking pan.
Whisk the cream cheese, sour cream and Erythritol until completely combined and consistency is smooth.
Whisk in the eggs one at a time.
Mix in the lemon juice, the zest and the vanilla essence.
Pour onto the base and bake for 1 hour.
Leave to cool and then refrigerate for a couple of hours or until completely cooled.
Then, preheat oven to 180°C.
Meringue: Whisk the egg whites until light and fluffy.
Add the Erythritol and whisk until stiff peaks form.
If you are using lemon curd (see my recipe http://cookpad.com/uk/recipes/11545347-keto-lemon-curd) spread a thin layer over the cheesecake.
Now pour the egg whites (meringue mix) over the cheesecake and bake for 8 to 10 minutes.
Let it cool a little and then placr in refrigerator for an hour.
