Step 1: . Preheat the oven to 220/gas 7. Grease and line a 23cm spring-form cake tin.
Step 3: 2. For the crust: combine the biscuit crumbs, butter, sugar, and cinnamon in a large bowl, then press into the bottom of the tin. Chill in the fridge while you are making the filling.
Step 5: 3. For the filling: cream the cheese and sugar together, beating well. Gradually add the egg, continuing to beat well. Stir in the flour, followed by the cream, vanilla, lemon juice and zests.
Step 7: 4. Pour into the prepared tin and bake for 15 minutes, then reduce the heat to 110C/ gas ¼ and bake for a further 45-55 minutes, until set but not browned.
Step 9: 5. For the cream topping: meanwhile, prepare the topping by mixing together the soured cream, vanilla and sugar in a small bowl.
Step 11: 6. Remove the cheesecake from the oven and raise the temperature to 180C/gas 4. Spread the topping over the cake and return it to the oven to bake for a further 5-10 minutes until set but not colouring. Remove from the oven and put into the fridge to chill overnight.
Step 13: 7. Carefully remove the outside ring before serving – it’s easier to leave the cake on the base.
Step 15: 8. For the blackberry topping: to make a glaze gently heat the jam with some water, pass through a sieve and then paint onto the top of the cake whilst still warm. Finish by covering with blackberries and a dusting of icing sugar.