In a large saucepan over medium high heat, combine butter, sugar, milk, and salt until combined.
Bring the milk mixture to full boil and cook until the temperature reads 230°F, (soft ball stage), turning the heat down to medium if the mixture boils to high.
Once the temperature reaches 230°F, remove syrup from heat and stir peanut butter and vanilla extract into the syrup until almost smooth.
Stir the oats into the peanut butter mixture, then quickly scoop and drop tablespoonfuls of the peanut butter balls onto paper lined cookie sheet. Cool completely.