Bring heavy cream to a soft boil and turn off heat. Set aside.
Combine butter and sugar in a medium size heavy bottom pot on medium heat. Do NOT use a small sauce pan, otherwise you will have a mess when the heavy cream goes into the hot sugar.
Allow butter and sugar to melt, stirring often. If sugar granules stick to the sides of the pot, wet a pastry brush with water and gently push the sugar down into the bottom of the pot. This may need to be done repeatedly until the sugar is fully melted.
The sugar and butter will look somewhat grainy for about 5-7 minutes, but eventually the sugar will start to turn amber and will begin to look smooth.
Once the sugar and butter mixture is a deep amber or almond color, remove from heat and vigorously stir in heavy cream. The caramel will seize up a little, so return the pot to medium low and continue to stir. The caramel and heavy cream will blend together after a minute or two.
To finish off, remove caramel from heat and add salt. Stir until combined and let cool for 30 minutes before transferring to a storage container. I recommend a glass container that can easily be reheated.
Refrigerate the caramel sauce for up to 3 weeks. This sauce is thicker, so place it in the microwave for 10-20 seconds to loosen it up if you are using it as a drizzle for ice cream or pie. Otherwise, it is very spreadable and can be used for any assortment of desserts!