In a large mixing bowl, cream together unsalted butter, granulated sugar, and peanut butter until light and fluffy, about 3-4 minutes.

In a separate bowl, combine all-purpose flour, cocoa powder, baking soda, and salt. Whisk these dry ingredients together until evenly mixed.

Add the beaten egg into the dough and mix until fully integrated.

Gently fold in chocolate chips to the cookie dough until they are evenly distributed.

Scoop about 1 tablespoon of dough, roll it into a ball, and create a small well in the center. Swirl in a teaspoon of peanut butter.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. Place the cookie balls on the sheet, spaced apart. Bake for 10-12 minutes.

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