In a medium bowl, place the chocolate, peanut butter, vanilla extract, and unsalted butter. Microwave the chocolate mixture on high for 30 seconds. Stir ingredients until well mixed.
Place the bowl back in the microwave for 20 more seconds. Stir until mixture is smooth and everything is melted.
Pour chocolate mixture over cereal. Take your hands and mix the cereal with the chocolate, making sure to coat all of the cereal. The chocolate will start to harden.
Dump the 2 cups of powdered sugar in the bowl and continuing mixing with your hands.
Spread the mix onto a baking sheet lined with wax paper and let it cool to room temperature (about 2 hours).
Store in an air tight container or a gallon sized zip lock bag and place in the fridge.