Make the dough
In an electric mixer fitted with the paddle attachment, cream together the butter and sugar on medium-high speed for about 3 minutes, until light and fluffy. Add the vanilla and egg and mix until just combined. In a separate bowl, whisk together the flours, salt, cardamom, and baking powder. Add the dry ingredients to the wet ingredients in two batches, stopping to scrape down the sides of the bowl as needed. Turn the dough onto a piece of plastic wrap and press it into a disk. Wrap and chill in the refrigerator for 2 hours, until firm but still flexible.
Make the filling
Combine 1/4 cup of the walnuts with the dates, cinnamon, orange juice, honey, and salt in a small saucepan and bring to a boil. Lower the heat and simmer uncovered, stirring often, for 5 to 7 minutes, until the mixture forms a thick paste. Transfer to a plate and let cool to room temperature.
Make the cookies
Line two baking sheets with parchment paper.
To make each cookie, wet your hands and break off a lemon-size piece of the dough. Flatten the dough, or make a well in it using your thumb. Place 1/2 tsp. of the filling in the middle, then pinch the dough closed and roll it into a ball. Flatten the dough gently between your palms to form a disk 1 inch thick, and place it on the lined baking sheet. Press a pinch of the remaining 1/4 cup walnuts into the center of the cookie. Repeat with the remaining dough and filling.
Refrigerate the cookies for 45 minutes, until firm. While the cookies chill, preheat the oven to 350°F.
Bake the cookies for 25 minutes, until the undersides are golden. Transfer to a cooling rack and let cool completely. In a clean spice grinder, grind the remaining 1/2 cup sugar into a fine powder. Dust the cookies with the powdered sugar and serve. Store in an airtight container at room temperature for up to 5 days.
Photo: Sara Remington © 2013
Reprinted with permission from The New Persian Kitchen by Louisa Shafia, copyright © 2013. Published by Ten Speed Press, a division of Random House, Inc.