In a large microwave-safe bowl, heat the chocolate chips, peanut butter, and butter in 30-second increments in the microwave. Stir after each increment until smooth. Add the vanilla, and stir to combine.
1 ½ cups semi-sweet chocolate chips, ¾ cup creamy peanut butter, ⅓ cup butter, ½ teaspoon pure vanilla extract
Add the Rice Chex cereal to the bowl and gently toss with a spatula to coat the cereal in the melted chocolate mixture.
9 cups Rice Chex cereal
When the cereal has been completely coated, spoon it into a gallon-size zip-lock resealable bag. (You may have to do this in batches if the bag is not big enough to hold all the cereal). Pour in the confectioners' sugar and seal the bag.
3 cups confectioners' sugar
Toss the cereal in the confectioners' sugar to coat.
When the cereal is completely coated in the confectioners' sugar, remove it from the bag and put it into a serving bowl.
Serve at room temperature.
Video
Notes
Storage: Once the puppy chow has completely cooled, you can store it in a sealed container at room temperature for up to 2 weeks.
Variations: You can substitute other types of Chex cereal (try Chocolate Chex if it's available!) or Crispix cereal. Milk chocolate, white chocolate, butterscotch, or peanut butter chips could be used instead of semi-sweet chips.