Lightly grease a 9x13 pan. Pour 5 cups Rice Krispie cereal into a large mixing bowl and set aside.
Combine the 1 cup corn syrup and the 1 cup granulated sugar in a medium-sized saucepan over medium heat. Heat until the granulation of the sugar is gone and the mixture has come to a near boil but do not let it actually boil. The temperature that you are looking for is about 199-200 degrees Fahrenheit.
Remove from the heat and stir in the1 cup peanut butter, 1 teaspoon vanilla and 1/2 teaspoon salt. Mix until smooth.
Pour the sugary, peanut butter mixture over the cereal and gently fold the cereal into the mixture until all is coated evenly.
Spread across the bottom of the greased 9x13 dish and spread out, gently pressing the mixture until it is even.