In a 3 quart saucepan, combine the corn syrup, granulated sugar and brown sugar. Bring to a boil over medium heat, stirring frequently. Remove from heat and stir in the peanut butter until smooth. Stir in the cornflakes and peanuts until coated. Turn into a greased 13x9x2 pan and press firmly and evenly into bottom. (for easier cutting, line pan with foil and grease the foil) Spread with melted milk chocolate. Cool thoroughly. Cut into bars and serve. If you like, melt together the semisweet chocolate and shortening to drizzle over the bars.