Butterfinger candy bars are a popular treat enjoyed by many people. The filling of a Butterfinger bar is made from a mixture of peanut butter and a crispy, crunchy center made from cornflakes. The peanut butter is combined with sugar, corn syrup, and other ingredients to create a smooth, creamy consistency. The cornflakes are crushed and mixed into the peanut butter mixture, giving the filling its distinctive crispy texture.