Lightly grease the base and sides of a 20cm x 30cm rectangular tray and line with greaseproof
Add the digestive and ginger nut biscuits into a food processor and whiz until finely crushed. Alternatively, you can add to a sealed bag and beat with a rolling pin.
On low heat melt the butter in a microwave or pan. Add this to the processor and pulse until the mixture is full combined. Add the biscuit base into the base of the prepared tin and smooth with the back of a spoon making sure to press it right into the corners and the base is all even. Chill in the fridge for at least an hour.
In a large bowl with an electric whisk beat the American style cream cheese until it represents soft peaks . Add the icing sugar, vanilla, lemon juice and zest, and beat again to combine. Pour in the cream and mix until you can feel the mixture thicken.
Tip the cheesecake mixture into the tin and level out with a spoon or spatula until smooth.
With your lemon curd blob evenly all over the cheesecake mixture then gently swirl through until you get a nice rippled effect. Chill in the fridge for at least 4 hours or preferably overnight until firm.
Cut into 24 cubes and serve.