1. Spray 13 x 9-inch baking pan with cooking spray. In large bowl combine cereal and 2 cups marshmallows; set aside.
2. In medium saucepan combine sugar and corn syrup. Stirring occasionally, bring to boil over medium heat and boil 1 minute. Remove from heat.
3. Stir in peanut butter until smooth. Pour over cereal; stir to coat. Press evenly into prepared pan.**
4. Drizzle melted chocolate over cereal layer; top with remaining 2 cups miniature marshmallows.
5. Arrange rack in oven or broiler so that top of baking pan is about 4 inches from source of heat. Preheat broiler. Broil S'mores 10 to 30 seconds or just until tops of marshmallows are lightly browned.
6. Cool S'mores. Cut into 2-inch squares.
Makes about 24 bars
* If using flake cereal, increase the amount to 8 cups,
** HINT: Slip a plastic bag over your hand before pressing mixture into pan.