In a medium saucepan, bring the cocoa, sugar, milk and butter to a boil over medium heat. It's important to bring these to a boil verrrrry slowly. Once they reach a rolling boil, boil for 60 seconds. Use a timer!
Pull the saucepan off the heat after boiling. Add in the oats, peanut butter and vanilla. Mix well.
Allow the mixture to cool for 1 minute and then drop by teaspoonfuls onto wax paper.