Chocolate-Caramel Cookie Bars

INGREDIENTS

• 4 1/2 ounces (9 tablespoons) unsalted butter, room temperature, plus more for parchment
• 1/4 cup packed light-brown sugar
• 1 1/2 cups all-purpose flour
• 1/4 teaspoon table salt
• 10 1/2 ounces milk chocolate, chopped (2 cups)
• 1 1/2 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