01 - Place the Chex cereal into a large mixing bowl and set aside.
02 - In a microwave-safe bowl, combine white chocolate chips and unsalted butter. Microwave for 30 seconds, stir, and repeat in intervals until melted and smooth, approximately 1–2 minutes.
03 - Stir pure peppermint extract into the melted chocolate mixture until fully incorporated.
04 - Pour the melted chocolate mixture over the cereal. Using a spatula, gently fold until all pieces are evenly coated.
05 - Combine powdered sugar and crushed peppermint candies or candy canes in a large zip-top bag or deep container with a lid.
06 - Transfer the coated cereal to the bag containing the powdered sugar mixture, seal, and shake thoroughly until cereal is evenly coated.
07 - Spread the mixture onto a parchment-lined baking sheet and allow to cool and set for 10 minutes.
08 - Mix in mini marshmallows and holiday sprinkles if desired before serving.
09 - Store snack mix in an airtight container at room temperature for up to one week.