Coat 13 x 9 x 2-inch microwave-safe dish with cooking spray. Arrange KEEBLER GRAHAMS ORIGINAL crackers in single layer in dish, breaking crackers as needed to fit. Sprinkle marshmallows evenly over crackers.
Microwave on HIGH 1 minute or until marshmallows are puffy. Remove from microwave. Cool completely.
In 2-quart microwave-safe mixing bowl combine chocolate morsels, corn syrup and butter. Microwave on HIGH about 1 1/2 minutes or until chocolate is melted, stirring every 30 seconds. Stir in peanut butter. Add KELLOGG'S® RICE KRISPIES® cereal, mixing until combined.
Spread evenly over marshmallows. Cover and refrigerate about 1 hour or until firm. Cut and store in airtight container in refrigerator.
Follow step 1 above using 13 x 9 x 2-inch baking dish coated with cooking spray. Bake at 375°F about 7 minutes or until marshmallows are puffy. Cool completely. In medium saucepan combine chocolate morsels, corn syrup and butter. Cook stirring constantly, over medium-low heat until melted. Remove from heat. Stir in peanut butter. Add KELLOGG'S® RICE KRISPIES® cereal, mixing until combined. Complete as in step 4 above.
Note: *Each cracker sheet measures about 5 x 2-inches and is scored into 4 pieces.