01 -
Adjust oven rack to the 2nd level position (just above center) and preheat the oven to 375°F (190°C). Line two cookie sheets with parchment paper or silicone mats and set aside.
02 -
In a medium bowl, whisk together the all-purpose flour, baking soda, baking powder, and salt. Set aside.
03 -
Using a hand mixer or stand mixer fitted with the paddle attachment, cream the unsalted butter, peanut butter, light brown sugar, granulated sugar, milk, and vanilla extract on medium-high speed until well blended. Add the egg and mix until incorporated.
04 -
Set the mixer speed to low and gradually add in the whisked dry mixture until completely blended.
05 -
Roll the peanut butter cookie dough into 2.5 cm (1 inch) balls, spacing them about 4-5 cm apart on the prepared cookie sheets. If using cookie stamps, coat them lightly with flour and press down on each dough ball. Repeat with remaining dough, re-flouring stamps every 2-3 cookies to prevent sticking.
06 -
If not using cookie stamps, roll the dough into 2.5 cm balls and place them 4-5 cm apart. Dip a fork in cold water, then create a cross-hatch or X pattern on top of each dough ball, gently pressing down.
07 -
Bake the cookies for 8-10 minutes at 375°F (190°C). Let them cool on the cookie sheets for about 5 minutes before transferring to a cooling rack. Use a spatula for transfer as they will be very soft.
08 -
In a medium microwave-safe bowl, heat the chocolate chips and vegetable shortening in 30-second increments, stirring between each, until completely melted and smooth. Dip a portion of each cooled cookie into the chocolate and sprinkle with chopped peanuts. Allow to set before serving.