In a large bowl, stir together oats and salt. Set aside.

In a small saucepan, over medium-high heat, whisk together butter, sugar, and milk.

Bring the mixture to a boil for about a minute and then remove from heat.

Whisk in peanut butter and vanilla until well combined.

Pour the peanut butter mixture over oats and stir until combined.

Line a baking sheet with wax paper. Drop cookies onto the wax paper using a medium cookie scoop.

Let the cookies cool on the countertop. Store in the refrigerator once cookies are cool and dry.