Place 3 cups of old fashioned oats into a large bowl.
Add butter, sugar, cocoa and milk to a small sauce pan. Stir frequently until bioling. Once mixture begins to boil, stir constantly for 2 minutes while continuing to boil.
After boiling chocolate mixture for 2 minutes, add the mixture to the oats.
Add the peanut butter to the oats and chocolate mixture and stir until well combined.
Using a cookie scoop or spoon, spoon out cookies onto a cookie sheet.
Let cookies sit for about 30 minutes until they harden. Store cookies in an airtight container.