Line a 22x33 cm (9x13 in) baking pan with wax paper or parchment paper. In a medium saucepan over medium heat, stir corn syrup and sugars until combined and bring to a boil, stirring occasionally. Immediately remove from heat. Stir in the peanut butter and mix well. Quickly stir in the vanilla and Rice Krispies and then spread into the prepared baking pan. Cool and slice into squares.