In a microwave-safe bowl, combine white chocolate chips and sweetened condensed milk. Microwave in 30-second intervals, stirring in between, until melted and smooth.
Stir in vanilla extract.
Fold in crushed Oreo cookies, reserving a few for topping.
Pour mixture into the prepared baking pan and spread evenly. Sprinkle reserved crushed Oreos on top.
Refrigerate for at least 2 hours or until set. Cut into squares and serve.