Preheat the oven to 190°C/Fan 170°C/Gas 5.

● Grease a 20cm springform cake tin and line the base with some baking parchment.

● Put the biscuits in a food processor and blitz them

to fine crumbs.

● Melt the butter in a saucepan, then stir in the biscuit crumbs. Tip this mixture into the prepared tin and smooth it to the edges with a spoon.

● In a free-standing mixer or with a hand whisk, beat the sugar with the cream cheese and mascarpone. Add the eggs, vanilla and lemon zest, then a squeeze of lemon juice and stir to combine.

● Carefully pour the mixture on to the biscuit base and gently shake the tin to level the top.

● Bake the cheesecake for 1 hour, covering the top with foil if it starts to look too brown.

● At the end of the hour, turn the oven off and leave the cake in the oven for 2 more hours until cooked through.

● Take the cake out of the oven and leave it to cool completely. Remove it from tin and dust the top with a little icing sugar before serving.