Double Chocolate Mint Cookies

In a large bowl, combine the flour, baking soda and salt. Pass the cocoa powder through a fine sieve into the bowl; whisk the mixture until evenly combined.

In the bowl of an electric mixer, beat the butter, brown sugar, granulated sugar and vanilla extract on medium speed until creamy, about 1 minute. Add the eggs and beat for about 2 minutes more, until light and fluffy. Gradually add the flour mixture and mix on low speed until incorporated. Add the chocolate and mint chips and continue mixing until just combined. Chill the dough in the refrigerator for 30 to 60 minutes, or until firm enough to handle.

Meanwhile, preheat the oven to 375°F (190°C) and set the oven racks in the middle and upper thirds of the oven. Line two baking sheets with parchment paper.

Scoop or roll the dough into walnut-sized balls and place on the prepared baking sheets about 2 in (5 cm) apart.

Bake for 9 to 11 minutes, or until the cookies are puffed and set. Cool the cookies on the baking sheets for 2 minutes, then transfer to a wire rack to cool completely. Repeat with remaining cookie dough. Store the cookies in an airtight container for up to three days.