Line a large baking sheet with waxed paper and set aside. Add popcorn, cereal and pretzels to a large bowl then toss to combine.

Add white chocolate chips to a microwave-safe bowl and melt by microwaving for 30 seconds. Remove from microwave, give the chocolate chips a stir then continue to heat and stir at 10-second intervals until chips are about 80% melted. Stir gently until the remaining chips have melted and become smooth.

Pour melted white chocolate over the popcorn mixture and stir or toss gently to coat ingredients completely. Transfer mixture to the baking sheet then spread it into an even layer but don’t compact the mixture.

Sprinkle with sea salt if desired then allow the chocolate to set at room temperature for an hour. Once chocolate is firm, break up any large clumps. Serve and enjoy!