Salted Caramel Sauce

Combine the sugar, corn syrup, and water in a medium saucepan. If using the vanilla bean, scrape the seeds from it and add the seeds and pod to the pan (if using extract, you will add it later). Bring the mixture to a boil over medium-high heat. You can stir the mixture before it comes to a boil to help dissolve the sugar but stop stirring the moment it starts to boil. Then continue to boil the syrup until it becomes a medium amber color. Once the syrup starts to color, tilt the pan occasionally—it’s easier to see the true color of the caramel when you’re looking at less of it (otherwise it may seem darker than it really is).

As soon as the caramel is close to medium amber, turn off the heat—the caramel will retain heat and continue to cook, so you want to allow for the carry-over cooking. Add the butter and stir gently to combine. Stir in the cream (be careful—the caramel is likely to bubble up and steam a lot; just keep stirring and it will die down). The sauce should be smooth and creamy. If it seized up and you see chunks of caramel, return the pan to low heat and stir occasionally until the sauce is smooth, then remove from the heat.

Stir in the salt and the vanilla extract, if using. Let cool to room temperature. The sauce may firm up as it sits. If necessary, rewarm the sauce in 15-second bursts in the microwave to make it more fluid.

Do Ahead: The sauce can be refrigerated in an airtight container for up to 2 weeks.