Line a 9x9-inch baking pan with wax paper, leaving the edges hanging over the sides of the pan.
Add the butter, corn syrup, brown sugar, vanilla, and salt to a heavy saucepan over medium heat and bring to a boil while stirring constantly. Boil for 1 minute before removing from the heat. Pour into a bowl with the oats and mix until fully coated. Pour into the prepared pan and smooth out the top. Refrigerate for at least 1 hour to firm up. Slice into bars. Top with a drizzle of melted chocolate if desired. Enjoy!
Notes
Add ¼ teaspoon of additional salt if using unsalted butter.
You can replace the corn syrup with honey if you don't mind a honey flavor in the bars. Golden cane syrup could also be used in place of corn syrup.
Pulse rolled oats in a food processor a few times to make quick oats in a pinch.
Store in an airtight container in the refrigerator for up to 5 days.