Place 6 3x1/2 in. cookie cutters on a 5 inch square of foil. Seal foil tightly around outside of cookie cutter. Place on cookie sheet. Lightly spray cookie cutters with cooking spray
In 4-cup microwavable measuring cup mix chocolate chips, peanut butter chips, milk and butter. Microwave uncovered on High 1 to 2 minutes, stirring every 30 seconds, until chips are almost melted -- stir in vanilla.
Pour mixture into cookie cutter molds, filling to tops of molds. Refrigerate uncovered about 2 hours or until firm.
Decorate fudge with icing and candies while still in molds. Carefully remove foil. Gently press fudge out of molds to serve.