Whisk together the flour, cocoa powder, baking soda, and salt. Set aside.
Using an electric mixer, beat the butter, granulated sugar, and brown sugar about 3 minutes or until fluffy. Add the egg and mix well. Stir in the vanilla.
Reduce mixer speed to low and add the flour mixture in three portions, mixing each just until incorporated. Stir in the chocolate chips and cherries. Refrigerate the dough for a few hours until firm.
Place the dough on a clean work surface and divide in half. Roll out into logs about 12 inches long and 1 & 1/4 inches in diameter. Refrigerate for about an hour. (Dough can be frozen for a month if wrapped well in plastic wrap and aluminum foil.)
Preheat oven to 350°F (175°C). Line baking sheets with parchment paper or silicone liners.
Cut the dough into 1-inch slices. Place the cookies 1 & 1/2 inches apart on the prepared baking sheets.
Bake (one pan at a time) for about 15 minutes, or until the cookies look just baked. Do not over-bake.
Cool the cookies on the pans on a wire rack for 5 minutes. Then transfer the cookies from the pan directly to a wire rack to cool completely.
Notes
Recipe was adapted from The Sweet Melissa Baking Book.
To store. Store double dark chocolate cherry cookies in an airtight container at room temperature for 3 to 5 days.
Freezing baked cookies. You can freeze baked cherry cookies for up to 3 months in an airtight container or freezer bag. Thaw them at room temperature, or warm them up in the microwave.
Freezing unbaked cookies. Alternatively, the unbaked dough can be frozen for a month if wrapped well in plastic wrap and aluminum foil. It can be frozen in a log, or you can freeze the dough after slicing it so you can bake just a cookie or two to satisfying a craving. Simply add a few additional minutes to the original baking time.