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
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.