In a large bowl, add crispy rice cereal squares and set aside.
In a saucepan over low heat, melt chocolate chips and butter together. Stir continuously to avoid burning. Alternatively, use a microwavable bowl; just microwave the mixture in 30-second intervals, stirring in between until smooth.
Once melted, add peanut butter to the chocolate mixture and stir until combined and silky smooth.
Stir in vanilla extract to the chocolate mixture.
Pour the chocolate mixture over the crispy rice cereal and use a spatula to gently fold until well-coated.
Transfer the coated cereal into a 2-gallon resealable food storage plastic bag, add confectioners' sugar, seal tightly, and shake until all pieces are coated.
Spread the coated mixture onto parchment or waxed paper in a single layer and let it cool until set.
Let it cool until the chocolate is set. This usually takes about 30 minutes.
Store your Puppy Chow in an airtight container to keep it fresh.
