Preheat oven to 375ยบ F. Line baking sheets with parchment paper or silicon baking mats
Heat butter and brown sugar in a 2-quart saucepan over medium heat, stirring frequently with a wooden or silicon spoon, until butter has melted and mixture is smooth. Stir in oats, flour, salt, egg, and vanilla
Drop cookie batter by the teaspoon onto prepared baking sheets, leaving about 2 inches between each cookie to allow them to spread
Bake for 5 -7 minutes, watching closely to prevent them from over-baking. The lace cookies should be golden brown
Allow to cool on the cookie sheet for 30 seconds and remove onto racks to cool completely