What could be better than an indulgent dessert made from ingredients you have sitting in your pantry and that never needs to go into the oven? These cookies take just minutes of work; most of the time is spent waiting for them to harden into the rich, nutty, chocolaty delights that they are.
Bring the sugar, milk, butter and cocoa to a boil in a medium saucepan over medium heat, stirring occasionally, then let boil for 1 minute. Remove from the heat. Add the oats, peanut butter, vanilla and salt, and stir to combine.
Drop teaspoonfuls of the mixture onto the prepared baking sheet, and let sit at room temperature until cooled and hardened, about 30 minutes. Refrigerate in an airtight container for up to 3 days.