First blend the hazelnuts till it’s a fine powder.
Then transfer it into a bowl and also add the sugar, the flour, the butter, the flaky salt, the instant coffee and the melted dark chocolate. Knead this till it’s a soft and even dough.
Now transfer it on a tray that’s lined with a silicon sheet and spread it.
Then bake it at 160 °C for around 25 minutes. Stir it every 5 minutes to create a fine crumble.
Then let it cool down completely and keep it dry and covered for later.