Line a 13×9 inch pan with nonstick foil. For a half batch, use an 8 inch pan.a large (3 quart) nonstick saucepan, combine sugar and corn syrup and heat just until mixture begins to boil and sugar starts to dissolve.
Remove from heat and stir in peanut butter and vanilla. Stir until well blended, then stir in the cereal.Empty the mixture into the pan and press firmly to cover.
Place chocolate and butterscotch chips in a microwave-safe bowl and heat on 50% power for about 2 minutes, stirring every 30 seconds, until melted and smooth. Alternatively, you can do this over a double-boiler.
Spread over top of bars and refrigerate until chocolate is slightly firm.
Remove from the refrigerator when set and return to room temperature (they are hard to cut when cold). Lift foil from pan and place on a cutting board.
