Butterscotch Bars without brownies crumbs

1 (18 1/4 ounce) package yellow cake mix 2 tablespoons water 1/3 cup butter or 1/3 cup margarine , softened 1 egg 4 cups miniature marshmallows 1 (11 ounce)[...]

1 cup butter , softened, plus or 1 cup margarine , softened 3/4 cup packed brown sugar , plus 2 tablespoons packed brown sugar 2 1/2 cups all-purpose flour 1[...]

3 tablespoons butter or 3 tablespoons margarine 1/2 cup brown sugar , firmly packed 2 cups miniature marshmallows 4 cups crispy rice cereal 2 cups corn flakes[...]