In a microwave-safe bowl, combine white chocolate chips, creamy peanut butter, and unsalted butter. Microwave the mixture in 30-second intervals, stirring after each interval to ensure even melting until completely melted and smooth, about 1-2 minutes total. Stir in the vanilla extract for added flavor.

In a large mixing bowl, pour in the rice cereal squares. Carefully drizzle the melted mixture over the cereal and use a spatula to fold everything gently, ensuring that all pieces are evenly coated.

Grab a gallon zip-top bag and add the powdered sugar along with a few drops of green food coloring. Seal the bag tightly and shake vigorously until the sugar takes on a uniform green hue.

Add the chocolate-coated cereal into the bag with the green powdered sugar. Seal the bag again and shake thoroughly until all pieces are covered in the vibrant sugar mixture.

Spread the coated cereal onto a marble surface or a baking sheet lined with parchment paper. Allow it to set at room temperature for about 5-10 minutes to become crisp.