Ingredients

• 1 vanilla bean, split lengthwise
• 1 cup demerara sugar
• 2 tablespoons bourbon
• Nonstick vegetable oil spray
• 10 ounce bittersweet chocolate (preferably 72%), coarsely chopped
• 4 ounces unsweetened chocolate, coarsely chopped
• 1 14-ounce can sweetened condensed milk
• 10 tablespoons (1 1/4 sticks) unsalted butter, cut into pieces
• 2 tablespoons bourbon
• 1 tablespoon light corn syrup
• 1/4 teaspoons kosher salt
• 1 vanilla bean, split lengthwise
• Flaky sea salt (such as Maldon)

Instructions

1. Preheat oven to 150° or as low as yours will go. Scrape vanilla seeds into a small bowl; stir in demerara sugar and bourbon. Spread on a parchment-lined baking sheet and let dry out in oven overnight, leaving door slightly ajar. Mixture should feel like demerara sugar again in the morning.
2. Line an 8x8" baking dish with parchment paper, leaving a generous overhang on 2 sides; lightly coat with nonstick spray. Heat chocolates in a heatproof bowl set over a saucepan of simmering water (do not let bowl touch water), stirring occasionally, until almost completely melted. Set aside.
3. Combine condensed milk, butter, bourbon, corn syrup, and kosher salt in a small saucepan; scrape in vanilla seeds and add pod. Heat over medium until barely hot (same as the chocolate).
4. Gently stir one quarter of milk mixture into chocolate with a rubber spatula. Add another quarter of milk mixture, stirring to incorporate (it might look broken and greasy; don't worry, it will come back together). Continue with remaining milk mixture in 2 additions, stirring vigorously until fudge is very shiny and almost elastic, about 5 minutes. Scrape into prepared pan and smooth top. Sprinkle with bourbon sugar and sea salt. Let cool, then cover and chill at least 4 hours.
5. Turn out fudge onto a cutting board and slice into 2x3/4" rectangles, 2" squares, or triangles.