In a medium bowl, combine the flour and salt, then sift them together. Set aside for later use.

Using a mixer fitted with the paddle attachment, beat the butter on medium-low speed for about 1 minute. Gradually add the sugar and continue beating for 1-2 minutes until the mixture is light and fluffy. Incorporate the vanilla extract and egg yolk. Lower the mixer speed to low and add the sifted flour and salt mixture, mixing just until the dough begins to come together. Be careful not to overmix, as this will make the dough tough.

Transfer the dough to a parchment-lined pan, spreading it evenly. I often use wax paper or a cupcake liner to create a barrier between my hands and the dough for a smooth, even layer. Bake at 350°F (180°C) for 15-20 minutes in a 12×17 inch pan or 20-25 minutes in a 9×13 inch pan. The shortbread should look slightly golden brown when finished. Let the pan cool on a wire rack while you prepare your caramel.

In a saucepan over medium heat, combine all the caramel ingredients: sweetened condensed milk, salted butter, brown sugar, light corn syrup, salt, and vanilla. Stir continuously while cooking the caramel.

When the mixture reaches a boil, reduce the heat to low. Depending on your heat settings, it may take 10-20 minutes of stirring for the caramel to come together. You’ll know it’s done when it easily pulls away from the sides of the pan and achieves a lovely golden color.

Remove the saucepan from the heat and immediately pour the caramel over the shortbread layer. Use an offset spatula to spread the caramel evenly for the best results. Allow it to cool in the refrigerator for at least 2 hours, or overnight if you prefer.

In a small saucepan, pour the heavy cream and place it on the stove over medium-low heat. After about 2 minutes, add the chocolate chips. Stir continuously until the chocolate chips have fully melted, resulting in a creamy and thick ganache.

Allow the ganache to rest for a minute or two before spreading it over the caramel layer. Again, use an offset spatula to evenly distribute the ganache on top of the chilled caramel. Sprinkle with sea salt and refrigerate for at least 1 hour to allow it to cool completely.

Store the bars in an airtight container in the refrigerator for up to one week.