Soften the butter a little in the microwave. Add the sugar and beat until a smooth cream forms.
Add the egg, the cocoa and the Nocciolata. Mix well. Add the flour, the salt, the water and the crushed hazelnuts.
Divide the mix between two cups and cook in the microwave for 1 minute and 30 seconds at 800W.
Leave to cool for two or three minutes before serving.
Serve with gelato or whipped cream. Keep in the fridge until ready to serve.