Prepare. Line a rimmed baking sheet with parchment paper or a baking mat. Also, place your cornflakes in a large mixing bowl.
Heat. In a large saucepan on medium-high heat, combine together the sugar and corn syrup, stirring constantly, bring it to a boil, allowing the sugar to fully dissolve. Then immediatly, carefully remove the saucepan from the heat and stir in the peanut butter and vanilla extract until the mixture is smooth and creamy.
Combine. Carefully pour the warm ingredients over your cornflakes in the mixing bowl and toss or stir until the cornflakes are well coated with the mixture.
Scoop. Use a small cookie scoop to scoop out the mixture and then drop each of the scooped ingredients on to your prepared baking sheet.
Toppings. You can add any optional toppings, such as sprinkles, over the scooped ingredients.
Set. Allow the candy to fully cool and set. I would not place the candy in a refrigerator as doing so can make them harder to chew.