In a large bowl add cereal and set aside. 

In a saucepan over low heat, melt the chocolate and butter; add peanut butter and mix until smooth or in a microwavable bowl add chocolate chips, peanut butter and butter. Microwave uncovered on high for 1 minute; stir. Microwave about 30 seconds longer or until mixture can be stirred smooth. 

Stir vanilla extract into chocolate mixture. Pour over cereal in a bowl. Stirring until evenly coated. Pour into a 2-gallon resealable food storage plastic bag. 

Add powdered sugar into a large plastic bag and shake until well coated. 

Spread on waxed paper to cool completely. After it is completely cooled add in M&Ms and peanut butter cups, gently stir to combine.

Store in an airtight container.