These are delicious. They are like a peppermint patty with an oreo layer. Pretty easy to make, just need a food processor and time (they are a bit time consuming, it seemed to me at least).
Preheat oven to 350 degrees F. Line an 9x13-inch baking pan with foil, extending foil over the pan edges; set aside.In a medium bowl, combine crushed cookies and melted butter. Press mixture into the bottom of prepared pan. Bake in the preheated oven for 8 minutes. Cool slightly in pan on a wire rack.Meanwhile, combine powdered sugar and softened butter in a food processor. Cover and process until butter is evenly distributed. With processor running, add milk and peppermint extract to make a paste. Spread peppermint mixture evenly over the prepared crust. Put in freezer for 45 minutes.In a saucepan, melt chocolate and shortening over low heat. Pour chocolate over mint layer and spread evenly. Freeze again, or let set out until chocolate in firm (I put in freezer for about 20ish minutes). Using the edges of the foil, lift the uncut bars out of the pan. Cut into square.
*I added Christmas sprinkles to the mint part, and snowflake sprinkles on top the chocolate part (before the chocolate hardens).
*adapted from HERE. The original recipe is in a 8x8 pan which I thought was way too small for the amount of time put into these, and I made a change in the peppermint layer part, I like more peppermint creme, so I more than doubled the original recipe, but don't worry, it's been tested and works just great.