Line an 8x8-inch baking pan with parchment paper, leaving some overhang on the sides for easy removal.
Place the peppermint Oreo cookies into a large zip-top bag and gently crush them with a rolling pin or use a food processor for a mix of fine crumbs and small chunks.
In a microwave-safe bowl, combine the white chocolate chips and the sweetened condensed milk. Heat in 30-second increments, stirring well after each until smooth and fully melted. Alternatively, use a double boiler on the stove.
Fold in about 3/4 cup of the crushed peppermint Oreos gently so they’re evenly distributed throughout the fudge. Reserve the remaining cookie pieces to sprinkle on top.
Pour the fudge mixture into the prepared pan and spread evenly with a spatula. Sprinkle the reserved crushed Oreos on top, pressing lightly so they stick.
Place the pan in the refrigerator for at least 2 hours or until the fudge is firm. Once set, lift the fudge out using the parchment paper edges and cut into bite-sized squares.
