In a medium pot over medium high heat, combine sugar, corn syrup, butter, salt and milk together.
Bring to a boil.
Once to a boil cook for 8 minutes, stirring constantly.
Remove from heat and mix in vanilla.
Let it cool for 20 minutes before serving.
When storing, cool completely and place in an airtight container. It can be stored in the refrigerator for up to 3 weeks.