Although many people feel they have to choose between a hard and soft caramel, Miette’s are right in the middle. The trick to controlling the texture is in the temperature, so you must use a candy thermometer and watch it very carefully. If you let the temperature rise above 246 degrees, the result will be a hard, chewy candy. If it doesn’t reach that temperature, the caramel will be gooey and pale. We make our caramels dark and buttery with flakes of fleur de sel to finish.
Butter the bottom and sides of an 8-inch square baking dish or casserole. Line the bottom with a piece of parchment paper long enough to extend over two opposite sides by about 3 inches, to use later as a handle, if needed.
In a medium saucepan, combine the cream, milk, granulated and brown sugars, salt, butter, corn syrup, and water. Clip a candy thermometer to the side of the pan. Place over medium-low heat and cook, whisking constantly, until the mixtures reaches 246 degrees, about 30–40 minutes.
When the caramel reaches the correct temperature, remove it from the heat and pour the hot caramel into the buttered pan, scraping out any caramel clinging to the sides of the pan. Be careful because the caramel is very hot. Let the caramel cool for 15 minutes and sprinkle with fleur de sel, then let the caramel cool completely to room temperature. Wrap the baking dish in plastic wrap and refrigerate the whole pan for at least 30 minutes and up to 1 ½ hours to help it set up and make cutting the caramels easier.
To remove the caramel from the pan, loosen the sides by running the tip of a knife around the edges. Lift the caramel out using the parchment paper “handles.” If it resists, warm the bottom of the pan briefly with a kitchen torch or over a stove burner. Turn the caramel out onto waxed paper on a cutting board. Measure 1-inch intervals along the sides, and then cut the caramel into 1-inch squares. Peel the caramel squares from the parchment paper.
Wrap each caramel in a square of waxed paper or candy cellophane and twist both ends. Store the caramels in an airtight container for up to 10 days.