Begin by greasing a 10-inch pie plate with unsalted butter and line it with parchment paper.

In a skillet over medium heat, toast 1.5 cups of walnut pieces for about 5 minutes until fragrant.

Stuff 30 pitted dates with the toasted walnuts and arrange them tightly in the prepared pie plate.

Melt 1 cup of unsalted butter in the skillet and gradually add 1.75 cups of all-purpose flour, stirring for 15-20 minutes until light tan.

Pour the butter-flour mixture over the packed dates and spread evenly.

Sift 0.5 cup of powdered sugar, 0.75 tsp of ground cinnamon, and 0.5 tsp of ground cardamom over the mixture, then sprinkle with 1 cup of pistachios or desiccated coconut.

Cover and let it cool at room temperature for several hours or preferably overnight.