Place the chocolate into a bowl and add the espresso. Set aside.
In a small bowl place the gelatine leaf in cold water to soak.
Combine half (100ml) the cream, glucose and sugar in a saucepan and bring to just before boiling point.
Microplane 1/4 of Tonka bean into the cream if using
Take off the heat
Squeeze excess water from the gelatine and add to the hot cream mixture. Stir until dissolved.
Pour over the chocolate and coffee.
Using a stick blender, create a smooth, silky mixture
Add the remaining (100ml) cream and blend again.
Cover directly with cling film onto the surface and place in the fridge for 2-3 hours.
To serve, whip the ganache to a light mouse just before serving.
Divide into serving dishes and garnish with Lindt chocolate decorations or a sqaure of Lindt EXCELLENCE