In a large mixing bowl, add shortening, peanut butter, brown sugar, egg, milk, vanilla extract and mix until combined and smooth.
Add flour, cocoa powder, baking soda and mix until just combined.
Stir in chocolate chips until evenly distributed.
Scoop out small portions of the dough and roll them into balls.
Note: If dough is too sticky, chill in fridge for 30-40 minutes to make it easier to handle. If dough is to dry, mix in a little more milk.
Place them on a cookie tray, lined with parchment paper.
Flatten them with a "criss-cross" pattern, using a fork.
Bake at 375 degrees F for 8-9 minutes or until edges are firm and center is slightly soft.
Remove from oven and allow them to cool completely in the pan and then, enjoy!