Grease eight small jelly moulds and line them with cling film.
Boil 250ml water, 250g caster sugar, and 250ml cranberry juice in a pan.
Simmer for five minutes before removing from the heat.
Stir in 25ml of vodka.
Squeeze excess water from the gelatine and stir into the hot mixture.
Stir until the liquid thickens slightly then transfer to a bowl.
Place blueberries into the bottom of each lined mould.
Fill the moulds with the jelly mixture and top each with a basil leaf.
Chill the moulds in the fridge overnight until set.
Mix Marsala, 125g icing sugar, and vanilla seeds in a bowl.
Add 250g blackberries and marinate for two hours.
Invert jellies onto plates and serve with the marinated fruit and double cream.