Add sugar and water into a saucepan over medium low heat. Stir until sugar has dissolved. Use a wet brush to remove any crystals that form on the side. Once sugar has dissolved increase heat to high. Now and then, using the handle give the pot a swirl to keep the mixture moving. Do not stir the mixture directly. The mixture will start to bubble after a minute. As the mixture darkens to a dark amber color, approximately 5-7 minutes, add the butter and cream to saucepan. The mixture will bubble wildly. Whisk to combine (bubbles will subside upon cooling). Add salt and stir to combine.