Source  Brown Eyed Baker

Recipe Added:  9/11/2014

Pour sugar evenly over the bottom of a heavy 2-3 qt saucepan. Heat sugar over medium-high heat, whisking it as it begins to melt. Stop whisking once all of the sugar has melted, and swirl the pan occasionally while the sugar cooks. Continue cooking until the sugar has reached a deep amber color. It should look almost a reddish-brown, and have a slight toasted aroma. This is the point where caramel can go from perfect to burnt in a matter of seconds, so keep a close eye. If you are using an instant-read thermometer, cook the sugar until it reaches 350 F.

As soon as the caramel reaches 350, add the butter all at once. Whisk the butter into the caramel until it is completely melted. Remove pan from the heat and slowly pour cream into the caramel. Whisk until all of the cream has been incorporated and sauce is smooth. Add salt and whisk to incorporate. Set the sauce aside to cool for 10 to 15 minutes and then pour into a glass jar and cool to room temperature. May refrigerate up to 2 weeks. Warm sauce before using.

1. http://www.browneyedbaker.com/homemade-salted-caramel-sauce-recipe/