Start by preparing your workspace. Line a baking sheet with parchment paper or set it aside for later use.

In a large bowl, measure out 9 cups of Rice Chex cereal and set aside.

In a microwave-safe bowl, combine the semisweet chocolate chips, creamy peanut butter, and unsalted butter. Microwave in 30-second increments, stirring after each, until fully melted and smooth. Be careful not to overheat.

Once melted, stir in the vanilla extract until well combined.

Pour the chocolate mixture over the Rice Chex cereal in the large mixing bowl. Gently fold the cereal until it is evenly coated with the chocolate mixture.

In a separate large resealable plastic bag, add the powdered sugar. Carefully transfer the chocolate-coated cereal into the bag, sealing it tightly.

Shake the bag gently until all the pieces of cereal are well-coated in powdered sugar. If desired, add the holiday-themed sprinkles and shake again.

Spread the coated cereal mixture onto the lined baking sheet and allow it to cool and set for about 15 minutes.

Once cooled, break into clusters and serve in a festive bowl or store in an airtight container for up to a week.