Instructions

1.  Heat the sugar in a saucepan stirring constantly ( best use a rubber spatula) till it has melted to a thick amber coloured liquid. DO NOT MOVE AWAY from your pot, stay and stir.  
2. Remove just for a second from the heat to cool it a bit and add gradually the butter, while back ont eh heat and stirring. The caramel will bubble rapidly so keep on top of it, lift the pan form the heat for a second if needed.
3. Once the butter is completely melted into the caramel, very very gently stir in the cream, this will make the mixture bubble up again. Be careful, and keep stirring. Allow the mixture to boil for a minute.
4. Remove from heat, stir in the salt and allow to cool before serving. Pour into a jar and refrigerate up to 2 weeks. You can reheat it in the microwave if you want to pour it onto ice cream for example.