01 - Line two baking sheets with parchment paper to prevent sticking.
02 - Combine butter, sugar, milk, and salt in a medium saucepan. Bring to a rolling boil over medium heat, stirring occasionally. Boil for exactly 1 minute.
03 - Remove saucepan from heat. Stir in peanut butter and vanilla extract until mixture is smooth and fully blended.
04 - Add oats to the saucepan and mix thoroughly to ensure even coating and distribution.
05 - Drop heaping tablespoons of the mixture onto the prepared baking sheets. Flatten slightly using the back of a spoon.
06 - Allow cookies to stand at room temperature for at least 15 minutes, or until completely firm.