Melt the Coating: Add the white chocolate chips, peanut butter, and butter to a large microwave-safe bowl. Microwave for 30 seconds, stir, then continue microwaving in 15-second intervals until the mixture is smooth and fully melted.
1 cup white chocolate chips, ½ cup creamy peanut butter, ¼ cup butter
Add the Vanilla: Stir in the vanilla extract until fully combined.
1 teaspoon vanilla extract
Coat the Cereal: Add the Rice Chex cereal to the bowl. Gently fold until all of the cereal is evenly coated with the melted mixture.
9 cups Rice Chex cereal
Add the Powdered Sugar: Place half of the coated cereal and half of the powdered sugar into a large zip-top freezer bag. Seal and shake until coated. Add the remaining cereal and remaining powdered sugar, then shake again until everything is fully covered.
2 cups powdered sugar
Cool the Mixture: Spread the coated cereal onto a baking sheet or large tray, or place it in a large bowl, and let it cool completely.
Finish the Mix: Once the puppy chow is cool, transfer it to a serving bowl and stir in the red, white, and blue chocolate candies and sprinkles, if using.
1 cup red, 2 tablespoons red
Serve or Store: Serve right away, or store in an airtight container at room temperature for several days. If your kitchen is warm, keep it in the refrigerator so the candy does not melt.