• Preheat oven to 350℉ (180℃)

Shortbread Crust

• Prepare a 9" cake pan or tart pan by spraying generously with non-stick spray. Cut a 9" circle of parchment paper and place in bottom of pan.
• Combine flour, cornstarch, brown sugar and salt in a large bowl.
  1 cup all-purpose flour, ¼ cup Light Brown Sugar, 1 tablespoon Cornstarch
• Add the cold butter cubes. Work the butter into the flour by squeezing between your fingers, Continue to work the butter and flour until no large chunks remain and the mixture looks mealy.
  ½ Cup Unsalted Butter, cold and cut into ¼" cubes
• Add the egg yolk and vanilla extract. Stir until the mixture is moistened and holds together when squeezed.
  1 large Egg Yolk, ½ teaspoon Pure Vanilla Extract
• Pour the dough into the prepared pan. Press evenly into the bottom of the pan. Using a fork, poke 10 - 15 holes in the dough.
• Bake for 18 - 20 minutes. Allow to cool before proceeding with the caramel layer.

Caramel Layer

• Use caution when making the caramel layer. The caramel can cause burns if it comes into contact with the skin.
• Place brown sugar, corn syrup, salt, butter and sweetened condensed milk in a medium saucepan. Whisk until well combined. Place the pan over medium heat and continue to whisk until the mixture begins boiling.
  1 14-ounce can Sweetened Condensed Milk, ½ cup Light Brown Sugar, 2 tablespoons Corn Syrup (light or dark), ½ teaspoon Sea Salt (finely ground), 6 tablespoons Unsalted Butter
• Insert a candy thermometer into the mixture. Continue to heat until the mixture reaches 225℉ (107℃) (approximately 5 minutes) , whisking constantly to ensure the bottom does not burn.
• Remove the pan from the heat once the mixture reaches 225℉ (107℃) . Immediately pour the caramel over the shortbread base. Allow to cool for 30 minutes.

Chocolate Layer

• Soften chocolate in the microwave: place in a bowl and heat on 50% microwave power for 30 second bursts, stirring between each heating. Chocolate will be partially melted.
  8 ounces Bittersweet Chocolate, finely chopped
• Heat heavy cream until it just starts to boil. Pour over the softened chocolate. Allow to rest for 3 - 4 minutes then stir until smooth. If all the chocolate does not melt, place back in microwave for another 30 seconds on 50% power.
  3 fluid ounces Heavy Cream
• Once the chocolate/cream mixture is smooth, pour over the caramel layer and spread evenly.
• Sprinkle coarsely ground sea salt over the chocolate. Place the pan in the refrigerator until set (approximately 1 hour).
  1 teaspoon Sea Salt, coarsely ground
• Cut into wedges using a knife run under hot water (this will create a smoother cut through the chocolate and caramel).