Line a 9x13-inch pan with a parchment or foil sling. Make the sling by cutting a piece of parchment or foil the length of the pan. Liner should be long enough to line the bottom of the pan and hang over both edges of the pan several inches. Grease the liner and sides of the pan. The sling allows easy removal of the entire crispy rectangle to a cutting board where you can cut into bars or star shapes.
In a small heavy bottom saucepan melt the butter and dulce de leche sauce over medium-low heat. Add marshmallows and stir continuously until marshmallows are melted.
Measure crispy rice cereal into a large bowl. Pour dulce de leche mixture over cereal and mix. Spread mixture into prepared pan. Allow to cool several hours.
Break chocolate into small pieces. Chocolate can be melted in a small heavy bottom saucepan over low heat or in a microwave in a glass bowl. Microwave in 15 second intervals, stirring each time until chocolate is completely melted and smooth.
Remove sling from pan and place on a cutting board. Cut into bars or into star shapes. Drizzle melted chocolate over each star and allow chocolate to harden before serving.
*Tip: If using a cookie cutter rinse and dry cutter when it gets too sticky.