The bottom of the small rectangular baking dish covered with cooking paper. Chocolate and the butter, together with 2 tbsp warm water, put in a saucepan over low heat and stir until a smooth mixture. Remove from heat and stir the vanilla essence. The mixture was poured into a tray, the top is sprinkled with cashews and put in the refrigerator for 3 h. Before serving is removed from the pan and cut into slices or cubes.