Melt together the butter, milk, cocoa, granulated sugar and salt. Cook over medium-high stirring constantly until the mixture comes to a boil.
Lower to medium and continue to cook for 2 minutes.
Remove from the heat and mix in the peanut butter and vanilla, stir constantly until the peanut butter begins to melt.
Add 2 cup oats, stir until coated and add additional ½ cup at a time. Work quickly.
Drop using a tablespoon on wax paper. Cool completely.
Notes
When making this recipe, there can be variables. Humidity, ingredient quality etc. I recommend adding oats until they're fully coated with chocolate as pictured. This may take less than 3 cups total..