Preheat the oven to 350 degrees F. Line a large baking sheet with a Silpat baking mat or parchment paper and set aside.

In the bowl of a stand mixer, beat the peanut butter and sugar together until creamy and smooth. Add in the egg and vanilla extract. Mix until well combined.

Add the baking soda, salt, and cocoa powder. Mix until just combined. Stir in the milk and mix until combined. Stir in chocolate chips. The dough will be a little crumbly and that is ok. It will press together when you form the balls.

Form the cookies into balls, pressing the dough together, about 1 1/2 tablespoons of dough per cookie. Place the cookies onto prepared baking sheet, about 2 inches apart. Gently press down on the dough mounds with the  palm of your hand to flatten. Bake for 10-12 minutes. Remove from oven and allow the cookies to cool for 5 minutes on the baking sheet before transferring to a wire rack to cool completely.

Note-I like to stick a few extra chocolate chips on top of the cookies before baking. Store cookies in an airtight container for up to 3 days on the counter. These cookies also freeze well!