Make up the sugar free jelly in a plastic jug using 400ml boiling water from the kettle. My sachet said to use a pint of water but I prefer a firmer set so always use less than the instructions say. Allow to cool until lukewarm.
Pour the unset, cooled jelly equally between four wine glasses. Allow 100mls per glass. Drop 5-6 raspberries into each glass.
Slice your chocolate sponge pieces into chunks around 2cm thick and no wider than the glasses. You will need around 8 pieces of sponge. Lay the chocolate cake pieces gently on the surface of the jellies submerging them slightly beneath the liquid. Allow to cool completely, then chill in the fridge for 3-4 hours until the jelly is set.
To make the custard, heat the cream in a medium size saucepan until it's not quite boiling then turn heat off. In another bowl, whisk the egg yolks with the sugar and vanilla extract until thick and creamy. Stir in the cream mixture beating all the while, and then returning to a low to moderate heat. Stir continuously for 8-10 minutes.
To thicken, decant a spoonful of the milky egg liquid into a glass and mix with 1 tbsp of cornflour. Return this to the pan and continue to stir on a moderate heat. Repeat with a further table spoon of cornflour until the custard goes very thick. It might be a little lumpy but don’t worry about that as we will be blending it soon.
When the custard is completely cold, stir in a few drops of pink food colouring and drop in the remaining raspberries. Use a hand blender to blend in the raspberries and this will also sort out any lumps in the custard.
To make the chocolate topping, melt the dark chocolate in a double boiler with the cream. When mixed thoroughly, pour the chocolate out onto a piece of baking parchment on a tray. Allow to cool and solidify. When completely cold and solid, use a table knife to scrape at the surface and make flakes or cut small pieces that you will later sprinkle on top of the trifles.
Remove the jellies from the fridge and spoon equal amounts of custard into the glasses.
Beat your double cream and cocoa powder with an electric mixer until it stands in peaks. You can either spoon directly on top of the custards or pipe it on with a star nozzle for a retro effect.
Spike pieces of the chocolate ganache into the cream. Return to the fridge to chill thoroughly. Serve cold.