Combine the butter, sugar, milk, and cocoa powder together in a medium saucepan over medium heat.
Whisk constantly until the butter melts. whisking occasionally, bring to a boil.
Once boiling, stop whisking and allow to boil for 1 min.
Remove from heat, then immediately stir in the peanut butter and vanilla extract until completely combined.
Stir in the oats and salt.
Allow mixture to sit for 5 min. This allows the oats to soak up some moisture.
During the 5 min, line two baking sheets with parchment paper or silicone baking mats. and make sure there is enough room in your refrigerator for the baking sheets.
Using a 1 tbsp cookie scoop, drop a tablespoon of dough onto the lined baking sheets. if desired, slightly flatten down with the back of a spoon. repeat with the rest of the dough.