In a saucepan over medium heat melt the butter and the milk together.
When the butter is just melted mix in the sugar and cocoa and bring to a full boil for one minute, stirring the entire time.
Remove from the heat and stir in the vanilla, peanut butter, and quick oats until thoroughly combined. Pour mixture into an 8x11 pan. Allow to set for about an hour.
Cut into squares. Enjoy!