Lay a large sheet of parchment or wax paper on the counter. Place sugar, milk, butter, salt and cocoa powder in a heavy bottomed sauce pan.
Bring mixture to a roiling boil over medium high heat.
Continue to boil for 2 minutes, stirring occasionally.
Remove from heat, add vanilla and peanut butter, stir to combine.
Stir in oats until well coated.
Using a 1 1/2 tbsp scoop, quickly scoop the mixture onto parchment or wax paper and leave to set.
Once set, the cookies will peel easily from the paper. Store in an airtight container.