In a medium saucepan over medium heat, melt ¼ cup of unsalted butter, then add ⅓ cup of light brown sugar. Whisk in ½ cup of heavy cream until the mixture thickens, about 5-7 minutes. Stir in a pinch of flaky sea salt and let cool.

In a large bowl, whisk together 2 cups of all-purpose flour, 1 tablespoon of cornstarch, 1 teaspoon of baking soda, and ½ teaspoon of fine sea salt. Set aside.

In a separate bowl, beat together ½ cup of unsalted butter, ½ cup of light brown sugar, and ½ cup of granulated sugar until light and fluffy, about 3-4 minutes.

Add a large egg and 1 teaspoon of vanilla extract to the butter mixture, mixing on low for about 30 seconds.

Gradually add the dry ingredients to the wet mixture, mixing until just combined. Gently fold in the warm salted caramel sauce, ensuring it swirls through the dough.

Preheat your oven to 350°F (175°C). Drop spoonfuls of dough onto a lined baking sheet, spacing them 2 inches apart. Bake for 12-14 minutes.

Sprinkle the warm cookies with flaky sea salt as soon as they come out of the oven. Allow to cool on the baking sheet for 5 minutes before transferring them to a wire rack.