Jersey Milk and Black Butter Caramels with Fleur de Sel

Prepare the pan: Line an 8x8 inch baking pan with parchment paper, leaving an overhang on all sides. Grease the parchment paper lightly with butter.

Combine ingredients: In a heavy-bottomed saucepan, combine Jersey milk, heavy cream, granulated sugar, and corn syrup. Cook over medium heat, stirring constantly until the sugar is dissolved.

Cook to caramel stage: Insert a candy thermometer into the saucepan. Continue cooking, without stirring, until the mixture reaches 245°F (118°C), the firm-ball stage.

Remove from heat: Remove the saucepan from the heat and immediately stir in the cubed butter, black butter, and vanilla extract. Stir until the butter is completely melted and incorporated.

Pour into pan: Pour the caramel mixture into the prepared baking pan. Sprinkle evenly with fleur de sel.

Cool and set: Let the caramels cool completely at room temperature for at least 4 hours, or preferably overnight, until firm.

Cut and wrap: Once the caramels are firm, use the parchment paper overhang to lift them out of the pan. Cut them into desired size squares using a sharp knife (dipping the knife in hot water can help). Wrap each caramel individually in wax paper.