Combine the sugar, water, and the corn syrup in a medium saucepan and stir over medium heat to dissolve sugar.

Cook for 3 minutes over medium heat with the lid on.

Take off the lid and increase the heat to medium-high, and bring to a boil.

Swirl (do not stir) the liquid around the pan so that the caramel doesn’t burn.

Keep cooking until the caramel turns an amber color then remove from the heat and let stand for about 30 seconds. Set your timer! Don't let it sit too long! - This is the trickiest part of the recipe. It make take a little practice to find the right amount of amber color.

Carefully pour the heavy cream into the mixture in a slow steady stream while mixing with a whisk. The mixture will bubble up significantly and is very hot.

Add the butter, lemon juice, and salt. Stir until combined.

Stirring occasionally, allow to cool until thick like molasses and warm to the touch, about 20 minutes.