In a saucepan, heat the granulated sugar over medium heat and start stirring. The sugar will start to form clumps and eventually melt into a thick, brown liquid as you stir. This part can be a little challenging as to make sure it doesn�t burn (Basically the part that everyone fears)
Add in the butter and immediately stir them together once the sugar has completely melted. The sugar (or now caramel) will start to bubble rapidly when you pour in the butter so be careful. If the sugar clumps up or the butter is separating, then remove the saucepan from heat and forcefully whisk for how long it may take to make sure all combined together. You can return back to heat when all seems to be combined.
Cook for 1 minute without stirring once the butter has melted and mixed with the caramelized sugar.
With the heavy cream, pour it into the saucepan and slowly stir it together. The bubble may arise as the heavy cream seems to be colder than the caramel. Stop stirring and leave to boil for 1 minute once all of the heavy cream has been added. As the mixture boils, it will rise in the pan.
Remove the saucepan from the heat and add in the salt. Allow to cool somewhat before using. As the caramel cools, it thickens.
Notes
If you cover it up tightly, you can store it up for 1 month in the fridge! When you want to use it, just reheat it on the stove or in the microwave according to your liking of the consistency.