Chocolate-Caramel Cookie Bars

Name: Chocolate-Caramel Cookie Bars
Prep time: 300 min
Cook time: 50 min
Total time: 350 min
Yield: 16 bars
Ingredients: 4.5 ounces (9 tablespoons) unsalted butter, room temperature, plus more for parchment; 1/4 cup packed light-brown sugar; 1.5 cups unbleached all-purpose flour; 1/4 teaspoon table salt; 10.5 ounces milk chocolate, chopped (2 cups); 1.5 cups granulated sugar; 1/4 cup water; 3 ounces (6 tablespoons) unsalted butter; 1 cup heavy cream; 1/2 teaspoon table salt; 1 tablespoon sea salt, preferably fleur de sel