Prepare the Baking Dish:

Line an 8x8-inch baking dish with parchment paper, leaving some overhang for easy removal.

Melt the Chocolate:

In a medium saucepan, combine the chocolate chips, sweetened condensed milk, and butter. Heat over medium-low, stirring constantly until the mixture is smooth and melted.

Add Vanilla and Salt:

Remove from heat and stir in the vanilla extract and a pinch of salt.

Incorporate the Butterfinger Candy:

Gently fold in ¾ cup of the crushed Butterfinger pieces, reserving ¼ cup for topping.

Pour into the Dish:

Pour the fudge mixture into the prepared baking dish and spread it evenly with a spatula.

Add Topping:

Sprinkle the reserved crushed Butterfinger pieces over the top, pressing them lightly into the fudge.

Chill and Set:

Refrigerate the fudge for at least 2 hours, or until firm.

Cut and Serve:

Once set, lift the fudge out of the dish using the parchment paper overhang. Cut into small squares and serve.