Combine the sugar and water in a small heavy-bottomed saucepan and bring to a boil over medium heat, stirring often until sugar has completely dissolved. Continue to boil, swirling the pan occasionally (but not stirring), until the mixture turns a deep amber color, about 10 to 15 minutes.
Remove the pan from the heat, carefully pour in cream and salt (the mixture will bubble up and steam), and stir until evenly combined. Return the saucepan to medium heat and bring to a boil. Remove from heat. Serve warm or cool (it will thicken as it cools) and refrigerate in a container with a tightfitting lid for up 5 days.