Stir sugar, corn syrup, and 2 tablespoons water in a heavy saucepan over medium heat until sugar dissolves. Increase heat to medium-high; boil, occasionally swirling pan and brushing down sides with a wet pastry brush, until deep amber color forms, 5-6 minutes. Remove from heat; gradually add vanilla cream (mixture will bubble vigorously). Whisk over medium heat until smooth and thick, about 2 minutes. Remove from heat; whisk in cold butter and salt. Strain into a heatproof measuring cup. Let cool slightly.