Line your pan: Line an 8x8-inch baking pan with parchment paper, letting it hang over the sides for easy lifting. Lightly grease the parchment to prevent sticking.

Prep the Oreos: Roughly chop the Oreos into chunks. You want a mix of big pieces and smaller crumbles for texture.

Melt the base: In a large microwave-safe bowl, combine the white chocolate chips and sweetened condensed milk. Microwave in 20–30 second bursts, stirring well between each, until smooth and fully melted. Do not overheat. Alternatively, melt in a saucepan over very low heat, stirring constantly.

Add peanut butter: Stir in 1/2 cup peanut butter, vanilla, and salt until silky and uniform. The mixture should be thick, glossy, and pourable.

Fold in Oreos: Gently fold in most of the chopped Oreos, saving a handful for the top. Don’t overmix or the cookies will turn the fudge gray.

Spread and top: Scrape the mixture into the lined pan and smooth the top with a spatula. Press the remaining Oreo pieces on top. If using, drizzle the melted peanut butter in thin lines and lightly swirl with a toothpick.

Chill to set: Refrigerate for at least 2–3 hours, or until firm enough to slice cleanly. For quicker setting, place in the freezer for 45–60 minutes, but don’t forget it there.

Slice and serve: Lift the fudge out using the parchment overhang. Warm a sharp knife under hot water, dry it, and slice into small squares. Wipe the knife between cuts for neat edges.