Add condensed milk, 2 cups powdered sugar, and peppermint extract in a large bowl. Mix on medium speed. Add powdered sugar 1/2 cup at a time, the dough will become stiff, so you may need to mix by hand at the end.

Roll 3/4" balls between your palms.

Flatten balls and place on partchment paper on a cookie sheet, place in freezer for 30-45 minutes to set up.

While dough is chilling place chocolate chips in microwave safe bowl and melt in 30 sec. intervals make sure you stir well. (If you decide you would rather use a double boiler start this before starting anything else.) Add the shortening once the chocolate is melted all the way.

Once the patties have set up completely dip into chocolate until completely covered. I found a fork is the best way to do this. Allow extra to drip off, then place on parchment or wax paper. I then place back in freezer to allow the chocolate to fully harden. It's ready when dry to the touch.