In a microwave-safe bowl, combine the butter, creamy peanut butter, and white chocolate chips. Heat in the microwave in 30-second intervals, stirring in between, until everything is melted and smooth. Be careful not to overheat; you want a creamy consistency.
Once melted, stir in the vanilla extract to enhance the flavor. This addition brings a lovely warmth to the mix that complements the sweetness perfectly.
In a large mixing bowl, pour the Rice Chex Mix. Carefully drizzle the melted mixture over the Chex. Using a spatula, gently fold the Chex into the mixture, ensuring each piece is evenly coated.
Once all the Chex are coated, sprinkle the powdered sugar over the mixture. Again, use the spatula to fold everything together until the powdered sugar is fully incorporated and each piece is covered in a sugary blanket.
Spread the Puppy Chow out on a baking sheet in an even layer to cool. Allow it to sit for about 30 minutes until set. Once cooled, transfer the Puppy Chow to a zip-top bag or a large container for storage.
