A delicious, creamy, indulgent dessert that tastes just like an excellent New York cheesecake, but is gluten free, has no added sugar, and is super simple to make - no water baths, excess ingredients or extra effort.
Preheat oven to 180C/gas 4. Line a 6" (15cm) loose-based cake tin with baking paper (cut a circle for the base and then a long strip slightly taller than the sides so it's completely lined and sticks out of the top of the tin a little).
Make the crust by pulsing nuts in a food processor to chop (chunkier will make for a crunchy base, but finer will be more delicate), then pour in melted butter, rice syrup (if using) and cacao powder (if using), and pulse until combined. Pour into the lined cake tin and press into a smooth, even layer along the bottom and slightly up the sides of the tin. Bake in the preheated oven for 10 minutes. Allow to cool while you make the cheesecake.
Mix the sour cream and vanilla and spoon over the top of the cheesecake. Return to the oven for 5 minutes, then allow to cool completely before chilling in the fridge for at least 3-4 hours, or overnight. Remove very carefully from the tin and serve cold on its own or with fresh berries, which cut through the richness. You could also crush some frozen berries and heat until warm to make a coulis for drizzling over.