Place all ingredients in a food processor. Process until everything is combined and you have a sticky consistency. Add 2 tbsp water if needed to reach this consistency.
Press well in a 20*20 cm square pan lined with parchment paper or aluminium foil. Refrigerate for at least 1 hour.
When solid, cut into bars.
Melt your chocolate in the microwave or using a bain marie. Dip each square in chocolate and decorate with some pistachios!