Name: Millionaire's Shortbread
Prep time: 15 min
Total time: 2 h 45 min
Yield: 40 - 48 serving(s)
Ingredients: 2 3/4 c. all-purpose flour; 3/4 c. granulated sugar; 1/4 c. cornstarch; 1/4 tsp. kosher salt; 1 c. plus 2 tbsp. unsalted butter, melted; 1 (14-oz.) can sweetened condensed milk; 1 c. light brown sugar; 1/2 c. unsalted butter, cubed; 1/2 c. light corn syrup; 1/3 c. heavy whipping cream; 1/2 tsp. kosher salt; 1 tsp. vanilla extract; 2 (4-oz.) bars bittersweet 60% chocolate, finely chopped; 1 tsp. coconut oil; Flaky salt, for sprinkling

Step 1For the shortbread: Preheat the oven to 350°F. Line a 13-by-9-inch baking pan with foil, allowing the edges to hang over the sides of the pan.

Step 2In a large bowl, combine the flour, sugar, cornstarch, and salt. Pour in the melted butter, stirring until a crumbly dough forms. Do not over-work the dough. Press the dough into the prepared pan in an even layer.

Step 3Bake until lightly golden, 25 to 30 minutes. Remove the pan to a wire rack and allow it to cool for 15 minutes.

Step 4For the filling: In a medium saucepan, stir together the sweetened condensed milk, brown sugar, butter, corn syrup, cream, and salt until well combined. Cook over medium heat, stirring frequently, until the mixture darkens, begins to pull away from the sides of the pan, and reaches 235°F, 12 to 14 minutes. Stir in the vanilla extract. Immediately pour the mixture over the shortbread crust, smoothing with a spatula. Allow to cool completely, about 1 hour.

Step 5For the ganache: Place the chocolate, cream, and oil in a glass measuring cup. Microwave the mixture at 50% power in 15-second intervals until the chocolate is melted, about 1 minute.

Step 6Pour the chocolate over the cooled caramel, smoothing it with an offset spatula. Sprinkle the surface with flaky salt.

Step 7Allow the bars to chill until set in the refrigerator, 30 minutes to 1 hour.

Step 8Using the foil edges, remove the bars from the pan and slice as desired.