Chocolate, Fruit and Nut Shortbread Cookies

Instructions

1. Put the peanuts and pistachios in the bowl of a food processor fitted with the chopping blade and pulse 4 or 5 times just to break up some of the nuts. You should have some pieces of finely chopped nuts, a few whole ones, and everything in-between.
2. Line a baking sheet with parchment paper. Place a closed upside down collar (groved side up) of a 9 or 10-inch springform pan in the center of the baking sheet. (Do not use the bottom of the pan.)
3. Add the butter and powdered sugar to the bowl of a standing mixer fitted with the paddle attachment. Beat on low speed for a few seconds just to mix the sugar in with the butter so it doesn't fly all over your kitchen, then on medium-high for about 4 minutes, until light and fluffy, stopping to scrape down the sides of the bowl from time to time.
4. Add the egg yolk and vanilla and beat on medium-high speed for about 30 seconds, until fully incorporated.
5. Add the flour and salt to a bowl, stir with a wire whisk to combine, then add to the butter mixture. Beat on low speed just until the dough is starting to come together, about 15-20 seconds. Add the dried fruit, nuts, and chocolate chips and mix on low speed just until incorporated.
6. Dump the dough into the center of the springform pan collar and press it into an even layer. Place a 2-inch biscuit cutter in the middle of the dough and cut out the center. Lay the round shortbread cookie on the baking sheet next to the springform collar and put the biscuit cutter back into the center of the dough.
7. Open the collar, but leave it in place. This will give the cookies some room to expand while baking. Cover the shortbread with plastic wrap and refrigerate for 1 hour.
8. Preheat the oven to 450 degrees. Remove the shortbread from the refrigerator, take off the plastic wrap, and bake for 5 minutes.
9. Reduce the oven temperature to 250 degrees and bake for 10-15 minutes longer, just until the edges are beginning to brown slightly.
10. Remove the cookies from the oven and turn the oven off. Use a sharp knife to score the shortbread into 16 wedges, cutting about halfway through the surface.
11. Return the shortbread cookies to the turned off oven and prop the oven door open with the handle of a wooden spoon so that there is about a one-inch gap at the door's opening. Let the cookies sit inside the warm oven for 30-45 minutes, until they are firm, yet yielding to the touch.
12. After 30 minutes, remove the one round shortbread cookie from the oven and let cool for about 5 minutes. Cut into it and taste for doneness. If it tastes done, remove the cookie sheet from the oven, place on a rest baking rack, and let sit, uncovered, for 2 hours.
13. Add the 3 oz of chocolate to a small bowl and melt in the microwave: cook for 1 minute at half power, remove and stir, and then continue to heat at half power in 30 second increments, stirring after each, until melted.
14. Remove the springform collar. Drizzle the cookies with the melted chocolate. Let sit for 30-60 minutes to allow the chocolate to firm up a bit, then use a sharp knife to cut along the scored lines into 16 wedges.
15. Store the cookies at room temperature in an air tight container for up to 1 week.