Place the wine and berries in a bowl and allow to steep for half an hour. Strain the wine into a saucepan and keep the raspberries to one side. Heat the wine with the vanilla pod until nearly boiling and leave to steep on one side for 15 minutes.
Soak the gelatine leaves – which you can find in the supermarket these days – in cold water for about 5 minutes. Meanwhile, after removing the vanilla pod, reheat the wine and stir in the sugar until it dissolves; allow to boil if you want to lose the alcohol.
Add a third of the hot wine to the wrung-out gelatine leaves in a measuring jug and stir to dissolve, then add this mixture back into the rest of the wine and stir well. Strain into a large jug.
Place the raspberries, equally, into six flattish, clear glass serving bowls, and pour the strained wine over the top.
Allow to set in the fridge for at least 3 hours, though a day would be fine if you want to make this well ahead, and take out of the fridge 15 minutes before serving.
Serve some double cream in a jug, and let people pour this into the fragrant, tender, fruit-jewelled jelly as they eat.