1. Preheat the oven to 350°F.

Peanut Butter Filling

1. In the bowl of your stand mixer fitted with the paddle attachment mix the peanut butter and powdered sugar together until smooth. Roll the filling into 24, 1- inch balls (mixture will be sticky). Place them on a parchment lined plate or baking sheet and chill in the freezer while you are making your cookie dough.

Cookies

1. In the bowl of your stand mixer fitted with the paddle attachment mix the butter, peanut butter and brown sugar together for 2 minutes on medium speed until light and creamy, scraping the sides of the bowl as necessary. Add in the vanilla, egg and extra yolk, cocoa powder, salt, and baking soda. Mix on medium speed for one minute until smooth, scraping the sides of the bowl as necessary.
2. Turn the mixer to low speed and slowly add in the flour. Mix until combined.
3. Remove the peanut butter balls from the freezer. Scoop out a heaping tablespoon sized amount of dough and form the dough around a peanut butter ball. Flatten the dough slightly so it’s not a round ball. Dip each into the granulated sugar and place on a parchment lined baking sheet 2 inches apart. Bake for 8-9 minutes until cookies are set and slightly cracked.
4. Transfer to a wire rack to cool completely.