Have all the ingredients and utensils ready for this recipe ahead of time. Use a heavy saucepan or saute pan with at least 2 quarts capacity, because the sauce will bubble up when the butter and cream are added. Make sure the utensils you are using are heat resistant. Have a plate handy to set the utensils on.

Put the sugar in the saucepan over medium heat and cook, stirring as needed with a wood or silicone spoon or spatula to prevent burned spots and break up lumps as the sugar melts. Keep cooking, stirring gently and breaking up lumps until the sugar has melted completely.

Once all the sugar has melted, stop stirring. Cook until the sugar is bubbling, has turned dark amber in color and reaches 350 degrees on a candy thermometer.

Remove the caramel from the heat and add the butter, blending with a wisk. The caramel will bubble up when the butter is added.

Add the cream and wisk to blend. The sauce will bubble up a second time.

Add the vanilla and salt.

Return the sauce to medium heat and boil gently, stirring with a wisk for about five minutes until thickened.

Remove from heat and let cool for about 15 minutes before pouring into glass jars.