Instructions

1. In a stand mixer fit with the paddle attachment combine the butter, brown sugar, and granulated sugar, beating until light and fluffy, about 2 minutes. Scrape down the bowl.
2. Add the egg yolks and vanilla extract and beat until fully incorporated.
3. In a separate bowl, combine the flour, baking powder, and salt. Mix to combine.
4. Add the dry ingredients to the wet and beat until combined and no streaks of flour remain. Last, add in the chopped chocolate.
5. Divide the dough in half and roll each piece into a cylindrical log, about 1 ½ inches diameter. Wrap in plastic wrap and place in the freezer for at least an hour (or freeze for up to 3 months).
6. When ready to bake, preheat the oven to 350°F and line a baking sheet with parchment paper. Use a very sharp thin knife to slice off ¼ inch thick cookies. Slice off as many as you want for the moment and rewrap and place the remainder of the dough back in the freezer. Bake the cookies for about 10 minutes, or until the edges are set and light golden brown. Allow to cool before enjoying with a glass of milk.