1Preheat your oven to 180°C (350°F) and line a baking sheet with parchment paper.
In a medium bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, and salt. Set aside.
In a large bowl, cream together the unsalted butter, brown sugar, and granulated sugar until light and fluffy.
Beat in the egg and vanilla extract until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the semisweet chocolate chips evenly throughout the dough.
Scoop tablespoon-sized portions of dough onto the prepared baking sheet, spacing them about 5 cm apart.
Bake for 10-12 minutes, or until the edges are set but the centers are still soft.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
Enjoy your delicious double chocolate chip cookies!