For preparing coffee-chocolate mousse, melt the chocolate pieces with butter and 2 tbsp of water.
Add in coffee essence and stir well.
Whisk the egg yolks and 20 grams sugar.
Add in the cream and whip again.
Then add in the melted chocolate mixture and remaining sugar. Whisk again.
In another bowl, whisk in the egg white with salt until stiff.
Fold in the egg whites with the chocolate-coffee mouse and chill it.
8)Chocolate-coffee mousse is ready. Serve chilled with vanilla or pistachio sauce.