Lightly coat a 9-inch square baking pan with nonstick spray. Line pan with two pieces parchment paper in both directions, leaving 2 inches of overhang on all sides; spray parchment. Place chocolate in a bowl. In a food processor, pulse candies until finely chopped. In a medium saucepan, combine candies, cream, marshmallows, butter, sugar, and salt over medium-high. Whisk until smooth, 5 minutes.
Pour mixture through a strainer into bowl with chocolate; let stand 1 minute, then stir until smooth. Pour into baking pan and refrigerate until set, 3 hours. Cut fudge into 1 1/2-inch squares. With a sharp knife, cut 18 candies in half; press a candy half into each square before serving or packing.
Use parchment or colored plastic wrap to package your fudge, or visit a crafts store for shiny, colorful foil squares. Twist the ends for a candy-like look, then stuff some stockings!