1teaspoonfleur de sel or other coarse sea salt, plus extra for sprinkling
1 ½cupgranulated sugar(300 grams)
¼cuplight corn syrup(60 ml)
Line an 8-inch square baking pan with parchment paper.
In a saucepan, bring the heavy cream, butter, and salt to just a boil. Keep warm.
Meanwhile, combine the sugar, corn syrup, and water together in a separate sauce pan over medium heat. Stir until sugar is dissolved. Once dissolved, stop stirring and let simmer until mixture turns an amber color. Watch closely that it doesn't burn, and swirl the pan as needed so that the mixture caramelizes evenly.
Remove from heat and add the cream mixture slowly while whisking constantly. Mixture will bubble violently. Once combined, stir in the vanilla. Return to heat and insert candy thermometer. Let cook, without stirring, until thermometer reaches 248°F.
Immediately pour mixture into prepared pan and let sit for 2 hours until firm. Sprinkle with additional salt and cut into 1-inch squares with a sharp greased knife. Wrap in 4-inch wax paper squares. Store at room temperature for up to 2 weeks.
Note: Fleur de sel can be found a fine grocery stores. Any other coarse sea salt can be substituted just fine.