Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, cream together the unsalted butter, light brown sugar, and granulated sugar until light and fluffy.

Add the eggs one at a time, incorporating each fully before adding the next, and then stir in the vanilla extract.

In a separate bowl, whisk together the all-purpose flour, baking soda, and salt, then gradually mix this into the wet ingredients.

Fold in the crushed Butterfinger candy bars, caramel bits, and chopped peanuts until well combined.

Drop rounded portions of dough onto the prepared baking sheet, spacing them about 2 inches apart.

Sprinkle sea salt flakes on top, then bake for 10-12 minutes until edges are golden.

Let the cookies cool on the sheet for 5 minutes before transferring them to a wire rack to cool completely.