I used extra dark cocoa powder and dark chocolate chips, so this is about the richest chocolate you can bite into short of a truffle.
This kind of shortbread cookie, with its short list of ingredients and easy prep is the ultimate holiday cookie. There's no stress involved, they come together in minutes, and the whole thing can be done ahead of time and the dough kept in the refrigerator or freezer.
Double Dark Chocolate Shortbread
(makes about 12-14 cookies, double the recipe if you want to)
oven to 325
1 stick (1/2 cup) unsalted butter, softened
1/4 cup confectioner's sugar
1/4 cup dark cocoa powder
1 teaspoon vanilla
3/4 cup all-purpose flour
1/2 cup dark chocolate chips
Cream the butter, cocoa powder and sugar together until completely combined and smooth. Add in the vanilla. Stir in the chocolate chips and turn the dough out onto a board and form into an smooth 8" log. The dough will be sticky. Wrap it in waxed or parchment paper and twist both ends to secure, shaping the log as you roll. Refrigerate for at least an hour, or overnight. You can also freeze the dough for later use. Slice the log into 1/3" slices with a sharp knife. Put on a parchment lined baking sheet and bake in the center of the oven for 12 to 15 minutes. They will feel slightly soft, don't over bake them. Cool for a few minutes on the pan and then transfer to a rack. If you're going to give them away make sure they are completely cool before you package them.