Place a few pieces of walnut in each date. Set aside.
Melt butter in a pan over medium heat. Add flour and stir constantly for 15-20 minutes, until golden. Set aside to cool down a bit.
Add the cardamom, powdered sugar and a-tablespoon cinnamon. Stir well.
Spread half of the flour mixture in an 8 inch flat dish.
Place the dates in a single layer on the flour mixture. Press them down.
Spread the remaining flour mixture over the dates and smooth out with the back of a spoon. Sprinkle with a layer of ground pistachios. Sprinkle a tablespoon powdered sugar and 1/2 teaspoon cinnamon.
Refrigerate and allow to cool before cutting into small squares with a sharp knife. Serve with a cup of tea.