Make sure the cream and butter are up to room temperature. Heat the cream in the microwave or on the stove if needed. The cream should be 70-80 degrees and the butter soft to the touch.
Start off by combining the sugar and water in a heavy bottom sauce pan.
Mix well and make sure all the sugar is dissolved. Once the stove is turned on do not touch the sauce! This is really important.
Turn the heat up to medium and bring the entire pot to a low boil. Make sure the entire pot is simmering. If just the outer edges are, adjust heat accordingly.
The sauce will turn from a clear color and then to a light brown and eventually a deep caramel color. I aim for it to closely match the color of my bourbon.
It can take up to 15 minutes for it to reach the right color.
Once it is the right color turn off the stove and move the pot off the heat.
Slowly, and carefully, pour in the heavy cream whisking while stirring. The sauce will bubble and foam up. This is normal. Just handle carefully.
Once all the cream has been added whisk in the butter until all melted and smooth.
Add in the bourbon and sea salt and whisk until incorporated.
Serve warm right away or allow to cool. It will get thicker as it cools.
Keep in a jar in the refrigerator up to a week. See reheating instructions below.