Scrape the seeds from half the vanilla pod into a saucepan with milk and bring to the boil.
In a clean bowl, whisk egg yolk, 50g sugar and cornflour until pale and thickened. Pour over the boiling milk to combine then return to the saucepan and simmer over a gentle heat until it thickens and coats the back of a spoon. Strain, then set aside to cool.
Soak the gelatine in cold water and stir until it swells. Drain gelatine and warm in a saucepan until melted, then stir in the raspberry puree. Leave to cool.
Pour the jelly into 6 glasses, spread with Griottines then cover with a sponge disc to fit the glass. Lace with Griottines juice.
Add an even layer of cold custard and top with a second sponge disc, lace with Griottine juice.
Whip cream until it forms soft peaks, then add 40g sugar and a few drops of vanilla extract and whisk again.
To serve, top your prepared jelly, sponge and custard layers with whipped cream and decorate with Griottines and chocolate discs.
Buy Griottines at www.griottines.co.uk
Use sponge cake or sponge fingers - the best quality you can get - and cut out to fit the glass.