Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
In a separate bowl, whisk together the flour, cocoa powder, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the dark chocolate chips.
Drop rounded tablespoons of dough onto the prepared baking sheet. Sprinkle each cookie with a pinch of sea salt.
Bake for 10-12 minutes, or until the edges are set but the centers are still soft. Allow cookies to cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.