Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.
In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy, about 2-3 minutes.
Add the egg and vanilla extract, and beat until fully combined.
Add the flour, cocoa powder, baking soda, and salt. Mix until combined.
Gently fold in the chocolate chips.
Scoop 3-tablespoon portions of dough (about the size of a large cookie scoop) onto the prepared baking sheet, spacing them a few inches apart.
Bake for 11–13 minutes, or until the edges are set but the centers still look slightly soft.
Let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.
Notes
For extra pretty cookies, press a few extra chocolate chips into the tops of the cookies before baking.
For deeper flavor, use dark chocolate chips or add a pinch of espresso powder to the dough.
Use any chocolate chips you like or have on hand! Dark chocolate chips will give your cookies a more intense chocolate flavor and less sweetness. Semi-sweet chocolate chips work wonderfully, too.