Prep the pan – Line a 9×13-inch pan with parchment or foil and spray lightly with cooking spray.
Melt candy corn & peanut butter – In a medium saucepan over low heat, stir candy corn and peanut butter together for about 3 minutes.
Add condensed milk – Stir in sweetened condensed milk. Cook for another 3 minutes, stirring often (don’t let it boil; a light simmer is fine).
Melt in white chocolate – Add white chocolate chips and stir until fully melted and smooth (it takes patience—keep stirring!).
Set the fudge – Spread the mixture evenly in the prepared pan. Let cool on the counter for 15 minutes, then refrigerate until firm (about 2–3 hours).
Add chocolate (optional) – Melt milk chocolate chips (add a little oil if you want it thinner) and drizzle over the top or dip the bottoms of the fudge squares. Decorate with festive sprinkles if desired.
Cut & serve – Slice into squares and enjoy the Butterfinger-like magic!