Begin by placing 9 cups of Rice Chex cereal into a large mixing bowl.

In a microwave-safe bowl, combine 1 cup of smooth peanut butter, 1 cup of chocolate chips, and ½ cup of unsalted butter. Microwave for 30 seconds, then stir and return to microwave in 15-second intervals until fully melted.

Stir in 1 teaspoon of vanilla extract into the melted mixture until fully incorporated.

Pour the melted mixture over the Rice Chex cereal and gently fold until every piece is covered.

Transfer the coated cereal to a zip-top bag, add 2 cups of powdered sugar, seal tightly, and shake until evenly coated.

Return the sugar-coated cereal to the mixing bowl and stir in 1 cup of red and green M&M's and any festive sprinkles.

Spread the mixture onto a baking sheet lined with parchment paper and allow to cool for about 30 minutes.

Once cooled, transfer the puppy chow into an airtight container for storage.