Line an 8 x 8" pan with aluminum foil; spray with nonstick cooking spray and set aside.
In a small saucepan over low heat, melt together 3/4 cup semi-sweet chocolate chips, 1/4 cup milk chocolate chips, 1/4 cup sweetened condensed milk and shortening, stirring until smooth. Spread mixture evenly in prepared pan. Chill for 5 to 10 minutes.
In a separate small saucepan over low heat, melt together white baking chips and 1/4 cup sweetened condensed milk, stirring until smooth. Remove from heat and stir in peppermint extract and food coloring. Spread evenly over chilled chocolate layer.
Melt remaining 3/4 cup semi-sweet chocolate chips, remaining 1/4 cup milk chocolate chips and remaining 1/4 cup sweetened condensed milk over low heat, stirring until smooth. Spread evenly over chilled mint layer.
Refrigerate for 2 hours or until completely set.
Remove candy from pan by lifting foil. Cut into small rectangles.