Preheat oven to 160 degC/320 Fahrenheit (not fan-bake). Grease and line the base and sides of a 20cm spring form cake tin with baking paper.
In a food processor, blitz all the base ingredients until well combined. The mixture should be a crumbly consistency and hold together well when pinched. If you don’t have a food processor, you can mash the dates with boiling water until they are very soft and then mix all ingredients together in a large bowl until well combined.
Tip base mixture into cake tin and press down firmly and evenly with the back of a large wet spoon, ensuring it is neat and flat.
In a large mixing bowl, use an electric mixer on low speed, to beat the cream cheese, sugar and vanilla until smooth. Beat in eggs, one at a time.
Melt chocolate in a double boiler or in a glass bowl over a pot of just simmering water. Stir in the sour cream, mixing gently until smooth.
Add chocolate mixture to cream cheese mixture and beat (on low speed) until well combined.
Melt jam in a small saucepan on low heat for 1-2 minutes or in the microwave very briefly.
Spoon half of the cheesecake filling into the cake tin, and drizzle over half to three quarters of the jam. Pour over remaining cheesecake filling, and drizzle over remaining jam. Bake for 1 hour until cheesecake is just set but still has a slight wobble in the middle.
Remove cheesecake from oven and leave to cool to room temperature before transferring to the fridge for a few hours, or overnight, to set.
When ready to serve, melt cherry jam in a small pot or microwave. Garnish cheesecake with fresh cherries, strawberries, raspberries and white chocolate shavings and drizzle over the jam. If using, fold all cinnamon yoghurt cream ingredients together and serve on the side.