Preheat your oven to 350°F (175°C).
In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Add in the eggs one at a time, beating well after each addition. Then mix 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 mixture, mixing until just combined.
Fold in the chocolate chips, if using, to the cookie dough.
Scoop tablespoon-sized portions of dough onto a parchment-lined baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 10-12 minutes, or until the edges are set but the centers look slightly underbaked.
Let the cookies cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely.
