1/4 c. butter
3 c. miniature marshmallows
3 c. Post cocoa or Fruity Pebbles cereal
1/3 c. peanut butter, when using cocoa pebbles (optional)

Melt butter and peanut butter in saucepan, stirring frequently. Add marshmallows and cereal. Remove from heat. Press mixture firmly into buttered 8 inch square pan. Chill 1 hour.