The microwave keeps preparation for these peanut butter-chocolate bar cookies short and simple. Briefly bake the oatmeal crust in the oven, then top with the cereal and peanut butter-chocolate fillings and let cool for 45 minutes.
Preheat oven to 350°. Combine first 5 ingredients in a medium bowl. Press firmly onto bottom of a lightly greased 15- x 10-inch jelly-roll pan. (Mixture will be thin.) Bake 12 minutes. Let cool on a wire rack 10 minutes.
Microwave corn syrup, sugar, and peanut butter in a large microwave-safe glass bowl at HIGH 2 minutes or until melted and smooth, stirring at 30-second intervals. Stir in cereal. Press mixture firmly over oat mixture in pan.
Microwave chocolate and peanut butter morsels in a microwave-safe glass bowl at HIGH 1 to 1 1/2 minutes or until melted and smooth, stirring at 30-second intervals. Spread over cereal mixture. Sprinkle with chopped peanuts. Cool 45 minutes. Cut into bars.
Note: We tested with Reese's Peanut Butter Chips and Rice Krispies cereal.