Preheat your oven to 350°F (175°C).
Melt the butter in a medium saucepan over low heat.
In a mixing bowl, combine the melted butter, brown sugar, vanilla extract, and egg. Whisk until smooth.
In another bowl, mix together flour and salt, then stir in the oats until coated.
Add the dry mixture to the wet ingredients, stirring until just combined.
Drop rounded tablespoons of dough onto a lined baking sheet, spacing about 2 inches apart.
Bake for 8-10 minutes, until edges are golden brown.
Cool on the baking sheet for a few minutes before transferring to a cooling rack.
