Preheat the oven to 350°F (175°C). Grease a 9x13 inch baking pan and line it with parchment paper.

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

Add the flour, oats, and salt to the mixture and stir until combined.

Press the mixture evenly into the bottom of the prepared baking pan.

Bake in the preheated oven for 15-20 minutes, or until lightly golden.

In a saucepan over low heat, combine the unwrapped caramel candies and heavy cream.

Stir continuously until the caramel is melted and smooth.

Pour the caramel over the baked base and spread it evenly.

Sprinkle the crushed Butterfinger bars evenly over the caramel layer.

Melt the milk chocolate chips in the microwave or over a double boiler.

Drizzle the melted chocolate over the Butterfinger layer.

Allow the bars to cool completely before cutting into squares.