Preparation

• Set a small dish of water and a pastry brush by the stove. Pour 1 cup water into a heavy-based 8-quart saucepan or Dutch oven. Add the sugar and corn syrup. Cook over high heat, stirring often with a wooden spoon, until the mixture is clear and comes to a boil. If sugar crystals form on the sides of the pan, wash them down with a wet pastry brush.
• Reduce the heat to maintain a gentle boil; it shouldn’t be spattering. Don’t stir but check frequently while boiling gently until the sugar begins to turn a light honey color in spots, about 20 minutes. Whenever sugar crystals form on the sides of the pan, wash them down with a wet pastry brush. Swirl the pan gently to even out the color. When the mixture reaches a rich, red-brown color, about another 8 minutes, take the pan off the heat. Slowly pour in the cream (be careful—the mixture will bubble vigorously and produce a lot of steam). Stir with a wooden spoon, making sure any solidified caramel on the pan bottom or sides melts. (If it doesn’t, set the pan over medium-low heat and stir gently until the caramel is completely smooth.) Stir in the butter and salt. Let cool to room temperature before stirring in the flavorings (if using; see Variations, below) and pouring into individual jars.

Espresso Caramel Sauce: Dissolve 3 Tbs. instant espresso powder into 2 to 3 tsp. hot water. Stir into the cooled caramel sauce to blend.

Orange-Cardamom Caramel Sauce: In a small saucepan, combine 1-1/2 cups fresh orange juice with 2 Tbs. plus 2 tsp. finely grated orange zest, bring to a boil, and cook until reduced to about 1/2 cup. Pour through a fine sieve, pressing against the zest to release all the liquid. Stir the strained, reduced orange juice and 4 tsp. ground cardamom into the cooled caramel sauce.