Stand 4 x 9cm mould rings on a baking sheet lined with greaseproof paper.
Prepare the biscuit crumbs by placing in a freezer bag and crushing with a rolling pin. I like to leave a few larger chunks among them so the base has a nice crunchy texture. Place the crushed biscuits in a bowl, add the melted butter and stir until well combined. Divide the biscuit mixture between the moulds and press into the base. Place in the fridge to set while you make the filling.
Put the mascarpone in a bowl, add the double cream and beat until soft and smooth. Add the lemon zest, juice and the sugar and mix well.
Fill each mould to two-thirds full then spread 2-3 teaspoons of lemon curd over the top. Finish by filling each mould to the top with the remaining mascarpone mixture and level off so the top is even and smooth. Put the cheesecakes in the fridge to chill for a few hours to set. Alternatively they can be placed in the freezer.
Make a glaze by warming and slightly reducing the apricot glaze and water in a saucepan. Top each cheesecake with some strips of lemon zest and brush gently with the apricot glaze. Finally pipe the melted white chocolate over the top using a paper cornet, or alternatively just drizzle over lightly. When you are ready to serve, use a blow torch or the warmth from your hands to gently warm the moulds and release the cheesecakes.