Rice Krispies Butterscotch Treats

3 tablespoons butter or margarine
1 (10 ounce package regular marshmallows, or
    4 cups miniature marshmallows or
    1 (7 ounce) jar Marshmallow Creme
3 tablespoons butterscotch instant pudding mix
6 cups Rice Krispies cereal

Melt butter in large saucepan over low heat. Add marshmallows or Marshmallow Creme and stir until completely melted. Remove from heat. Stir in butterscotch pudding mix. Add cereal. Stir until well coated. Using buttered spatula or wax paper, press mixture evenly into 13 x 9-inch pan coated with cooking spray. Cut into 2-inch squares.