Preheat the oven to 350°F and line two baking sheets with parchment paper.
In a large bowl, beat the butter, brown sugar, and granulated sugar until fluffy.
Add eggs and vanilla, mixing until smooth.
In another bowl, whisk together the flour, cocoa powder, baking soda, and salt.
Gradually stir the dry ingredients into the wet mixture until just combined.
Fold in the semisweet chocolate chips and dark chocolate chunks.
Scoop dough onto the baking sheets, leaving space between each cookie.
Bake for 9–11 minutes until edges are set but centers look slightly soft.
Let cookies cool on the sheet for 5 minutes before transferring to a wire rack.