Line a rimmed cookie sheet with foil and set aside.

Over medium heat combine sugar and corn syrup in a large saucepan and cook until bubbling at the edges, stirring occasionally. Cook, stirring, one minute more. Remove from heat and stir in peanut butter until melted. Stir in rice and corn cereals until completely coated. Press mixture into the lined cookie sheet.

In saucepan over low heat, melt 3/4 cup unsalted butter. Remove from heat and stir in powdered sugar, vanilla pudding mix and milk. Spread pudding mixture over the cereal layer in the pan.

In microwave or in a saucepan over low heat, melt chocolate chips and 1/2 cup butter. Stir until melted and creamy, spread over pudding mixture in pan.

Refrigerate for one hour to set. Lift bars out with foil and cut into squares or triangles.