Measure out 9 cups of Rice Chex cereal.

In a microwave-safe bowl, combine 1 cup of semi-sweet chocolate chips, ½ cup of creamy peanut butter, and ¼ cup of unsalted butter. Microwave in 30-second intervals, stirring after each, until smooth and well combined.

Pour the melted chocolate mixture over the Rice Chex cereal in your large mixing bowl. Gently fold the cereal with a rubber spatula until every piece is evenly coated.

Line a cookie sheet with parchment paper.

Transfer the coated cereal to a large zip-top bag. Add 1½ cups of powdered sugar, seal the bag, and shake until all pieces are coated.

Spread the Puppy Chow mixture onto the prepared cookie sheet in an even layer.

Let the Puppy Chow cool completely at room temperature.

Once cooled, break apart any clumps and serve.