Line an 8x8 baking pan with parchment paper and spray with non-stick spray.
Melt 1 1/2 cups chocolate chips with 3/4 cup sweetened condensed milk over low heat, stirring occasionally.
Spread mixture into prepared pan and chill until set (about 10 minutes).
Melt white chocolate chips and remaining condensed milk, stirring until smooth.
Remove from the heat.
Add peppermint and food coloring.
Spread this layer over refrigerated chocolate layer and chill until set (about 10 minutes).
Melt remaining 1 cup of chocolate chips with 1 tsp shortening in the microwave by heating 30 seconds and stirring and repeating until completely melted.
Spread over refrigerated layers.
Refrigerate until fudge is set (about 1 hour).
Cut into squares.