Add condensed milk, 2 cups of powdered sugar, and peppermint extract to a large mixing bowl. Mix everything on medium speed using the paddle attachment until all the ingredients are well incorporated. Add more powdered sugar, ½ cup at a time, until the dough is stiff but still pliable.
Roll ¾″ balls of dough between the palms of the hands.
Press each ball down slowly and set the flattened disk on a flat cutting board or plate. Transfer peppermint disks to the freezer for no longer than 30 minutes. While the dough is chilling, temper the chocolate coating.
Place chocolate chips in a microwavable bowl. Melt the chocolate in 30 second increments, making sure to stir after each time until chocolate is smooth. Stir in shortening to thin the chocolate. Remove patties from the freezer.
Place a patty on the tines of the fork and dip in the chocolate until completely covered. Allow excess chocolate to drip off the patty before setting each one on top of wax or parchment paper.
Allow the chocolate coated peppermint patties to completely set up. This can be done quicker by placing the patties in the refrigerator. The peppermint patties are ready when they are dry to the touch. Enjoy!
Recipe by Savory Sweet Life at https://savorysweetlife.com/peppermint-patties/