Prepare the Pan: Line an 8x8-inch baking dish with parchment paper. Set aside.

Cook the Base: In a large saucepan over medium heat, mix sugar, butter, and evaporated milk. Bring the mixture to a boil and cook until it reaches 234°F on a candy thermometer.

Add Chocolate and Peanut Butter Chips: Remove from heat and stir in chocolate chips and peanut butter chips until melted.

Incorporate Marshmallows and Vanilla: Add marshmallows and vanilla extract, stirring until marshmallows are melted.

Mix in Butterfinger Pieces: Gently fold in 1 cup of chopped Butterfingers.

Set the Fudge: Transfer the fudge to the prepared pan and sprinkle the remaining ½ cup of Butterfingers on top. Allow the fudge to set at room temperature or chill in the refrigerator to speed up the process.

Serve: Once set, slice the fudge into squares and serve at room temperature.