In a large sauce pan, add granulated sugar and place over medium heat. Whisk constantly until sugar starts to clump (normal) and then melt and turn a dark amber color. Careful not to burn. If the pan seems too hot, lower the heat.
Whisk in butter until melted, about 1-2 minutes. The mixture will bubble which is normal.
Slowly Whisk in heavy whipping cream. The mixture will bubble up again, let boil for 1 minute then take off the heat.
Whisk in vanilla and salt.
Pour into a jar and let cool.
Caramel can be stored in a sealed container in the refrigerator up to 2 weeks. Warm caramel up in the microwave for about 20 seconds when ready to use.