Preheat your oven to 350°F (175°C). In a large mixing bowl, cream together unsalted butter, granulated sugar, and brown sugar using an electric mixer for 3-5 minutes until light and fluffy.

In a separate bowl, whisk together all-purpose flour, cornstarch, and salt. Gradually add the dry ingredients to the creamed butter mixture, mixing gently until combined.

Fold in semi-sweet chocolate chips, reserving a small handful for topping later.

Grease a 9x13-inch baking dish. Spread half of the dough evenly across the bottom, layer with caramel sauce, then drop spoonfuls of the remaining dough and sprinkle reserved chocolate chips on top. Bake for 20-25 minutes.

Once baked, cool in the pan for 10-15 minutes before transferring to a wire rack to cool completely before slicing into bars.