White Chocolate and Blueberry Cheesecake

For the base:
175g / 6 oz toasted hazelnuts
50g / 2 oz icing sugar
50g / 2 oz butter, melted, plus more for the pan

For the filling:
400g / 14 oz white chocolate
2 x 500g tubs of fromage frais
11g sachet of powdered gelatine

For the jelly topping:
11g sachet of powdered gelatine
350g / 12 oz blueberries
50g / 2 oz caster sugar
juice of 1/2 lemon

Process the hazelnuts and icing sugar in a food processor or blender until the nuts are finely chopped. Pour in the melted butter and process again. Press the mixture firmly on the base of a lightly buttered 23cm / 9 in loose bottomed flan pan and chill.

Make the filling: break the chocolate into pieces and melt in a bowl set over a pan of gently simmering water, stirring until smooth. Remove from the heat; beat in the fromage frais.

Sprinkle the gelatine over 5 tablespoons of boiling water in a small bowl, then stir until dissolved and translucent. Stir into the fromage frais mixture, pour over the hazelnut base and chill.

Meanwhile, make the jelly topping: sprinkle the gelatine over 4 tablespoons of cold water in a small bowl and set aside to soak.

In a pan, heat half the blueberries, the sugar, lemon juice and 300ml / 1/4 pint of water, until the liquid is boiling and purple in colour. Stir in the soaked gelatine and remaining berries, remove from the heat and cool.

When the jelly mixture has cooled, spoon it over the top of the cheesecake and return to the fridge for about 3 hours until set.

To serve, carefully run a wet knife round the top of the cheesecake to loosen the jelly before removing from the tin.