9 cups Chex or Crixpix cereal
1 cup semi-sweet chocolate chips
1/2 cup peanut butter
1/4 cup butter
1 tsp. vanilla (I actually forgot to add this, and it didn't seem to make a difference)
1 1/2 cups powdered sugar
Measure cereal into a large bowl. Microwave chocolate chips, peanut butter and butter for 1 minute; stir. Microwave an additional 30 seconds, or until smooth when stirred. Stir in vanilla. Pour mixture over cereal and mix until evenly coated. Pour into 2 gallon resealable bag. (I used two 1 gallon bags--this is all I had, and it allowed 2 kids to shake) Add powdered sugar; seal bag and shake until well coated.
You can spread on wax paper to cool and store in the refrigerator in an airtight container. I just leave it in the bag on the counter.