Place the butter, sugar, milk, and unsweetened cocoa powder in a saucepan and heat over medium heat.
Stir often until the butter is melted and all ingredients are combined.
Bring the mixture to a boil and allow to boil for 60 seconds (please watch the time...timing is important) stirring occasionally. In fact, set a timer!
Remove saucepan from heat.
Stir in peanut butter and vanilla extract until fully combined.
Stir in oats and mix until all of the oats are coated with the mixture.
Drop spoonfuls of mixture onto parchment paper.
Cool cookies completely before serving or storing. Cookies gently harden as they cool.
