Heat the oven to 180°C, 160°C fan, gas 4. Line the base and sides of a 3 x 20cm, straight-side cake tins with baking paper.
Put all the cake ingredients in a large bowl and beat together with an electric whisk until smooth and very creamy. Divide the mixture evenly between 3 tins.
Bake for 30-35 minutes or until a skewer inserted into the centre comes out clean. Leave to cool.
Whip the cream until it is just thickened, don't over whip. Put one sponge layer on a serving plate. Spread generously with Wild Blueberry Conserve. Add half the cream and spread to within 2cm of the edge.
Repeat with the second sponge and the Raspberry Conserve.
Top the last sponge with mixture of fresh fruits and herbs. Dust with icing sugar and any left over pistachio crumbs.
Layer up the cake, add a length of bunting and some Jubilee decorations. Keep chilled in the 'fridge and serve within an hour.
Edible Union Jack bunting is available to buy online, or make non-edible bunting from coloured paper. Stick to thread with edible glue or sticky tape and hang on wooden skewers.
