Place the 150g Walnuts on a baking tray and bake for 5-8 minutes until golden. Place straight in a high-speed blender and mix until it forms a smooth Walnut butter, adding 1 tsp water if it looks too dry.
Place the chocolate in a bowl over and pan of simmering water over a low heat and allow to melt, cool slightly.
Split open the dates and lay out on a sheet of parchment paper to form a rectangle, 5 dates down and 4 dates across (approx. 14x16cm). Top with another sheet of parchment and bash with a rolling pin until flattened. Remove the top sheet of parchment.
Spread with the Walnut butter and then pour over the chocolate and spread until evenly coating the rectangle. Sprinkle with the chopped Walnuts and chill until set.
