Preheat the oven to 350°F (175°C) and line two baking sheets with parchment paper or a silicone baking mat.
In a medium bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, and salt. Set aside.
In a large bowl, beat the softened unsalted butter, brown sugar, and granulated sugar together using an electric mixer or whisk until light and fluffy.
Beat in the eggs, one at a time, then add the vanilla extract. Mix until fully combined. Gradually add the dry ingredients into the wet mixture, mixing just until incorporated. Be careful not to overmix.
Stir in the dark chocolate chips, semi-sweet chocolate chips, and chopped dark chocolate (if using).
Use a spoon or cookie scoop to portion out 1 ½-inch balls of dough onto the prepared baking sheets. Leave about 2 inches of space between each cookie.
Place the baking sheets in the oven and bake for 10-12 minutes, or until the edges are set and the centers are slightly soft.
Let the cookies cool on the baking sheets for 5 minutes before transferring them to a cooling rack to cool completely.