Preheat your oven to 350°F (175°C) and grease the baking pan.
In a mixing bowl, combine the crushed graham crackers, melted butter, and granulated sugar. Press this mixture into the bottom of the baking pan.
In a saucepan over medium heat, combine the sweetened condensed milk, unsalted butter, brown sugar, corn syrup, and vanilla extract. Stir until smooth and bring to a boil. Pour this caramel mixture over the crust.
Bake in the preheated oven for 25 minutes or until the caramel is bubbly. Remove from the oven and let it cool.
Once cooled, sprinkle the chopped Butterfinger bars, chocolate chips, and crushed pretzels over the top.
Refrigerate until set, then cut into bars and serve.
Notes
You can customize the topping by adding your favorite candies or nuts.