Line an 8x8 square pan with tin foil and lightly coat with nonstick baking spray.
Pour the white chocolate chips and sweetened condensed milk into a microwave-safe bowl. Microwave the bowl for 30 seconds and stir to combine.
Place back in the microwave for 15-second intervals until everything melted. Stir after each interval until the chocolate chips and sweetened condensed milk is smooth and creamy.
Add the peppermint extract and half of the crushed peppermints to the melted chocolate and stir until the peppermints are evenly distributed.
Pour the fudge into the prepared pan.
Sprinkle the remaining peppermints on top of the fudge and lightly push the crushed peppermint into the fudge to make the pieces stick.
Cover and refrigerate for several hours to allow the fudge to firm up.
Slice and enjoy!
Cover and place in the fridge. Best enjoyed within a day or two as the peppermints become sticky after a few days.