Using an electric mixer, cream together the softened butter, granulated sugar, brown sugar, eggs, and vanilla extract on medium speed until the mixture is light and fluffy.
In a separate bowl, whisk together the all-purpose flour, cocoa powder, baking soda, and salt until evenly combined.
Gradually add the dry ingredients to the butter mixture while mixing on low speed. Continue mixing until everything is well combined, stopping occasionally to scrape down the sides of the bowl.
Stir in the chocolate chips using a spatula until evenly distributed throughout the dough.
Cover the dough and refrigerate for at least 2 hours. If the dough is too firm to scoop after chilling, allow it to sit at room temperature for 10-15 minutes to soften slightly.
Preheat your oven to 350°F (175°C).
Line baking sheets with parchment paper or silicone baking mats.
Drop rounded tablespoons of dough onto the prepared baking sheets, spacing them about 2 inches apart.
Bake for 8-10 minutes, or until the edges are set but the centers are still soft.
Allow the cookies to cool on the baking sheets for 3-5 minutes before transferring them to wire racks to cool completely.