Preheat oven to 350°F (175°C) and line two large baking sheets with parchment paper.

In a large mixing bowl, cream the softened butter, granulated sugar, and brown sugar together until light and fluffy, approximately 2 minutes.

Add eggs one at a time, beating well after each addition, then stir in the vanilla extract.

In a separate medium bowl, sift together the flour, cocoa powder, baking soda, and salt.

Gradually incorporate the dry ingredients into the butter mixture on low speed until just combined.

Fold in the chocolate chips by hand using a rubber spatula.

Scoop rounded tablespoons of dough onto the prepared baking sheets, spacing them 2 inches apart.

Bake for 9 to 11 minutes, or until the edges are set but the centers remain slightly soft and puffed.

Allow cookies to cool on the baking sheet for at least 5 minutes before transferring to a wire rack to cool completely.