Mix first four ingredients in a medium saucepan over medium heat.
Cook for 6 minutes, stirring constantly, until everything has melted together and has slightly thickened.
Optional: Add vanilla and cook for an additional minute.
Remove from heat and allow to cool for 20 minutes in the saucepan before transferring to a jar with lid. Keep refrigerated, lid on, until ready to use.
Recipe by Slice of Jess at https://sliceofjess.com/super-simple-salted-caramel-sauce/