Preheat the oven to 350 degrees F and lightly coat a baking sheet with cooking spray. Sift the flour, cocoa powder, baking soda and salt into a medium bowl and set aside.
With a hand or stand mixer, cream the butter and both sugars until fluffy. Add the eggs, vanilla and peppermint extracts and mix well.
Add the dry mixture to the butter mixture and mix well. Stir in the chocolate chips and mint chips.
Roll the dough into 1 1/2-inch balls and place them on the prepared baking sheet. With two fingers, press the cookies down to about 1 inch thick, keeping the cookies about 2 inches apart.
Bake for 15 to 18 minutes, or until not glossy. Let the cookies cool on a wire rack.
Photograph by Jon Paterson/Studio D
Recipe courtesy of Duff Goldman for Food Network Magazine