Start by preheating your oven to 350°F (175°C). Grease a 9x13 inch baking dish or line it with parchment paper for easy removal later.
In a large mixing bowl, cream together the softened unsalted butter, light brown sugar, and granulated sugar until the mixture is light and fluffy. This should take about 2-3 minutes.
Next, add in the eggs, one at a time, mixing well after each addition. Pour in the vanilla extract and continue to mix until everything is well combined.
In a separate bowl, whisk together the kosher salt, baking soda, and all-purpose flour. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Gently fold in the semisweet chocolate chips, ensuring they are evenly distributed throughout the dough.
In a microwave-safe bowl, combine the unwrapped caramels and sweetened condensed milk. Microwave in 30-second intervals, stirring in between, until the mixture is smooth and fully melted.
Spread half of the cookie dough into the prepared baking dish, pressing it down evenly. Pour the caramel mixture over the dough, spreading it gently to cover. Then, take the remaining cookie dough and drop spoonfuls over the caramel layer, creating a rustic top.
Bake the bars in the preheated oven for 25-30 minutes, or until the edges are golden brown. The center may look slightly undercooked, but it will continue to set as it cools.
As soon as you remove the bars from the oven, sprinkle the flaked sea salt over the top for that perfect sweet-and-salty balance.
Allow the bars to cool in the pan for at least 20 minutes before transferring them to a wire rack to cool completely. Once cooled, cut them into squares and enjoy!
