Cut a sheet of acetate into 12 5 cm wide strips.
In separate bowls, over hot water , melt the white chocolate and the 250g of dark chocolate consecutively.
Smear the white chocolate intermittently over one side of the strip, when the chocolate has slightly dried, paint the dark chocolate liberally over the same side, taking care to cover completely.
Bring the ends together with the chocolate on the inside, and curl to fit inside a metal ring.
Do the same with the other strip and curl in the opposite direction and place in the other half of the metal ring, this should form a 'ying yang' shape.
Refrigerate for at least 15 minutes.
Bring 320ml double cream to the boil in a saucepan. Break the chocolate into small pieces if necessary and place in a heatproof bowl.
When the cream comes to the boil, pour the cream onto the chocolate and stir until all of the chocolate has melted and you have a glossy ganache. Allow the ganache to cool slightly for around 5 minutes.
In another bowl, lightly whisk the remaining 430ml double cream until it just begins to thicken.
Fold this cream into the ganache until evenly distributed.
Transfer the mixture to a piping bag
Pipe the mousse into the center of the chocolate teardrops and pipe until it fills the moulds.
Drain the cherries and push lightly into the center of each.
Chill for 30 minutes.
When set, remove the metal ring and carefully unravel the acetate sheets.
Serve immediately or keep covered and chilled.
«The acetate sheets can be reused if washed and dried correctly. Be careful not to leave the moulds uncovered in the fridge for too long as they will attract condensation and soften.»