In a large mixing bowl, whisk together flour, sugar, walnuts, cinnamon, cardamom, salt, baking powder, dates, and chocolate chips until well combined. Add applesauce and oil and stir until moistened. Transfer batter to prepared baking dish. Sprinkle with coconut and bake for 25 minutes or until a toothpick entered in the center of the bars comes out clean. Cool for approximately 10 minutes before turning out onto a wire rack to cool. If desired, sprinkle with powdered sugar.