Sea Salt Caramels

1 . Stage

Grease the baking sheet with the 1 teaspoon butter, and set it aside on a heatproof surface.

2 . Stage

Combine the sugar, evaporated milk, heavy cream, and vanilla bean and seeds (if using) in a large (6- to 8-quart) saucepan. Bring to a boil over medium-high heat, uncovered and without stirring.

3 . Stage

Once the mixture has come to a boil, insert the candy thermometer. Add the light corn syrup, and stir gently with the spatula until everything is mixed well. Reduce the heat to medium-low and cook, stirring often and making sure to scrape the bottom of the pot to keep the mixture from burning, until the mixture reaches 230 degrees F (thread stage), about 30 minutes.

4 . Stage

Add the 3 1/2 tablespoons butter. If you used a vanilla bean, fish it out with a slotted spoon. Stirring continuously, cook the caramel until it reaches 241 degrees F (soft-to-firm ball stage), 15 to 20 minutes; it will be a deep tawny color and have slow, rolling bubbles in the center. Remove it from the heat.

5 . Stage

Stir in the salt and vanilla paste or extract (if using), making sure they’re distributed evenly. Put on oven mitts and carefully pour the caramel onto the prepared baking sheet. Allow it to cool completely until it’s firm to the touch, at least 3 hours, preferably overnight. (If it’s humid, cover the caramel tightly with plastic wrap and store it at cool room temperature until you can cut and wrap it in wax paper.)

6 . Stage

Lightly oil a sharp chef’s knife with cooking spray, and run the tip around the edge of the baking sheet to release the caramel. Gently turn the caramel out onto the lined cutting board, and cut it into 1-inch squares. Wrap the pieces in wax twisting paper (to turn the squares into little logs, fold each piece over on itself, wrap the twisting paper around it and roll the wrapped caramel against the cutting board, then twist the ends of the paper shut).

7 . Stage

Store the caramels in an airtight container, at cool room temperature for up to 4 weeks; they’ll last for up to 3 months in the refrigerator.