In a saucepan, over medium-high heat, melt butter and add sugar, milk and cocoa. Mix well and bring to a boil for 1 minute.
Remove from heat and add peanut butter. Stir into mixture until well melted and combined. Add vanilla and then oats, mixing well.
Drop by 1/4 cupfuls onto wax paper. Shape into circles with a spoon and let cool to harden. (if yours don't harden, the temperature and humidity outside play a large part with these cookies) They still taste good though! Grab a spoon!