Preheat the oven to 160 °C/ 320 °F (fan assisted).
Mix the ground almonds and butter in a bowl to form a dough.
Lightly grease a non-stick 9 inch/ 23 cm loose bottom cake tin to prevent sticking.
(Line the base with greaseproof liner if required.) Press the almond mix into the base of the tin and cook for 10 15 minutes until golden.
Remove from the oven and allow to cool.
Turn up the oven to 180 °C/ 355 °F (fan assisted).
Add the erythritol, arrowroot and cream cheese to a mixing bowl.
Whisk using an electric whisk until combined.
Add the eggs and beat well.
Slowly add the cream and whisk till smooth.
Stir through the lemon zest and vanilla.
Spoon the mix onto the base and level with a spatula.
Loosely cover with tin foil and bake in the oven for 30 minutes.
(This prevents the cheesecake going too brown on top).
Remove the tin foil and cook for a further 10 minutes.
Remove from the oven.
Loosen around the cake sides with a palate knife.
This prevents the cheesecake cracking as it cools.
Allow to fully cool and then place in the fridge to set (4 hours to overnight).
Whip the cream until thick.
Spread evenly on top of the Keto cheesecake using a palate knife.
Slice and serve! Store in fridge for up to 3 days or freeze for up to 1 month.
Option to blitz the fresh blackberries and serve on top.