Instructions

• Line an 8 x 8-inch baking pan with parchment paper, leaving a 2–3 inch overhang on two opposite sides for lifting. Spray the parchment lightly with cooking spray. Set the pan aside.
• In a small saucepan combine the 1 cup heavy cream (do not substitute whole milk or half‑and‑half), ½ cup unsalted butter, ½ cup unsweetened cocoa powder, and 1 tablespoon instant espresso powder (do not use regular ground espresso). Heat over medium‑high, stirring nearly constantly, until the butter has fully melted and the mixture is smooth.
• Remove the small saucepan from the heat, stir in 1 teaspoon pure vanilla extract, then set this chocolate‑cream mixture aside.
• In a separate high‑sided saucepan (nonstick preferred; it must be high‑sided to prevent boiling over) combine 1 cup granulated sugar and 1 cup corn syrup (do not substitute). Cook over medium‑high heat, stirring constantly, until the sugar has dissolved.
• With the sugar/corn syrup bubbling but the heat still on, slowly pour the reserved chocolate‑cream mixture into the sugar mixture while stirring constantly to combine.
• Attach a clip‑on digital candy thermometer to the side of the saucepan and bring the mixture to a boil. Continue to cook until the mixture reaches exactly 245°F. This can take 20–30 minutes; do not leave the pan unattended. Monitor the boil and stir as needed to prevent scorching.
• When the mixture reaches 245°F, remove the pan from the heat. Using potholders and extreme caution, pour the hot caramel into the prepared parchment‑lined pan.
• Let the caramel sit undisturbed for about 7 minutes, then, if desired, sprinkle flaky sea salt on top to taste (do not add the salt while the caramel is still very hot or it will dissolve).
• Allow the caramel to set at room temperature for 5–6 hours (do not refrigerate or freeze, as that can negatively affect texture).
• When set, lift the caramel slab from the pan using the parchment overhang and place it on a cutting board. Use a very sharp knife (grease the blade with a little butter if you like) to cut into pieces of your preferred size.
• Wrap individual caramels in wax paper or decorative wrappers (parchment can be used but does not seal as well). Store airtight at room temperature for up to 1 month; refrigeration is not recommended.