Makes 2 cups
2 cups granulated sugar
1 cup heavy cream
2 tablespoons cold unsalted butter, cut into quarters
1 tablespoon rye or bourbon whiskey (optional)
1 teaspoon flaky sea salt
1 vanilla bean, split and scraped
1. Combine sugar and ½ cup water in a stainless-steel saucepan; stir. Using a pastry brush dipped in water, wet down sides of pan, cover, and cook over medium heat until sugar is dissolved and mixture is steaming, about 6 minutes.
2. Remove cover from saucepan; raise heat to high. Cook without stirring for 8–10 minutes, gently swirling pan, until mixture starts to turn color. Decrease heat to medium; watch carefully, swirling until mixture turns a deep amber color.
3. Wearing a mitt, remove pan from heat and immediately pour in cream. It will sputter temporarily. As it calms down, add butter. Whisk until smooth.
4. Add whiskey (if using), salt, and vanilla pod and seeds. Cool slightly, then remove vanilla pod and transfer caramel to a heatproof glass jar. Cool completely. Store in refrigerator. Rewarm to a liquid consistency before using.