Boil sugar, syrup and salt together for about 10 minutes.
Heat cream and condensed milk together in another saucepan. (Sugar and syrup should be boiled in a large, heavy saucepan.)
Do not allow cream to boil, just keep warm. Add cream mixture slowly to boiling syrup ( 2 or 3 tablespoons at a time), but do not let the mixture stop boiling. (time to clip on your thermometer making sure it doesn't touch bottom of pan)You should always calibrate your thermometer before cooking caramels (or any kind of candy). Here’s how to do it.....Fill a pot with 4-6″ water, then affix the thermometer at least 1 inch below the water line.Bring the water to a boil.Allow the water to boil at least 10 minutes.Check the temperature of the thermometer. Water boils at 212°F degrees, so if your thermometer isn’t reading that temperature precisely, it’s off. Once caramel starts to boil, continue cooking until the caramel reaches 230° and then start to test for "soft ball stage." This takes approximately 16-18 minutes to get to this point, all the while stirring constantly.
If you are unsure what "soft ball stage" means, get a small bowl of cold water and once the temperature reaches 220° drop a little caramel into the cold water and see if it feels soft, but somewhat firm between your fingers. Keep testing for the firmness with the "soft ball stage" method. Once the caramel reaches the desired texture and temperature, remove from heat. Cook to 245 degrees, and add vanilla and nuts. Pour into buttered pan. Two 9x9 inch pans are good, or if you want a deeper caramel use 1 large pan. If desired you can sprinkle coarse sea salt over the caramel. This salt really enhances the flavor of the caramels by providing a contrast to the sweetness.
Let set overnight and cut into squares. Wrap in wax paper, or dip in chocolate.
Store wrapped caramels at room temperature in an airtight container, where they will remain fresh for a little more than two weeks.
Now you can lick the spoon...absolutely heavenly!