Roughly chop the Swiss brown mushrooms and place in a cold pan with butter and cook over low heat. Remove as much water as possible from the mushrooms while gently cooking, then set aside to cool.
Combine espresso, sugar, water and Kahlua together in a saucepan to make coffee syrup and bring to a simmer. Set aside to cool down.
Combine sponge fingers and dark chocolate together in a processor and blend only until it is slightly crushed, then stir in the Swiss brown mushrooms.
Soak the crumble with the coffee syrup until it is damp. Then layer the bottom of the jar with the soaked sponge. Set aside in the fridge.
Soften gelatine in cold water.
Whisk eggs and sugar together over a bain-marie until fluffy. Then add in espresso, whisk.
Melt in gelatine.
Whisk egg whites with sugar to a meringue and then fold into the sabayon.
Whisk cream and mascarpone together until medium peak. Fold in cream to the sabayon.
Transfer mixture into a piping bag and pipe into the jar on top of the soaked sponge.
Blend all the ingredients together and strain into a siphon gun. Charge twice with cream chargers.
Poke holes in the bottom of a paper cup and siphon the sponge mixture half way.
Cook in the microwave for 45 seconds and rest upside down until cooled down.
Remove the stalks of the mushrooms and finely slice to make thin crescents. Place 3 pieces of hazelnut sponge on top of the mascarpone mousse and place 5 slices of mushrooms randomly. Then lightly dust with cocoa powder and mushroom powder.
Recipe by Reynold Poernomo