Yield: 24 cookie bars
2-1/8 cups all-purpose flour
1/2 teaspoon baking soda
1/2 teaspoon salt
12 tablespoons unsalted butter, melted and cooled to room temperature
1 cup light brown sugar
1/2 cup granulated sugar
1 egg yolk
2 teaspoons vanilla extract
2 cups chocolate chips
10 ounces caramel candy squares, unwrapped
3 tablespoons heavy cream
3 teaspoons (approximately) fleur de sel, sea salt, or kosher salt, for sprinkling over caramel and bars
Preheat oven to 325 degrees F. Grease a 9-inch square pan; set aside.
In a medium bowl, whisk together the flour, baking soda, and salt; set aside.
Using an electric mixer, mix together the melted butter and sugars on medium speed until combined. Add the egg, egg yolk, and vanilla extract and mix until smooth. Slowly add the dry ingredients and mix on low, just until combined. Stir in the chocolate chips.
In a medium microwave-safe bowl combine the caramels and heavy cream. Microwave on high until the caramels are melted, stirring every 20 seconds. This will take about 2 minutes. OR you can do this step on your stove top: melt caramels and heavy cream in a medium-sized pot or saucepan, stirring until melted.
Press half of the cookie dough into the prepared pan. Pour the hot caramel over the dough cookie dough and spread into an even layer, leaving some empty space around the edges. Sprinkle the caramel with half the sea salt. Drop the remaining cookie dough in spoonfuls over the caramel and gently spread the dough with a spatula until the caramel is covered. Sprinkle the bars with the rest of the sea salt.
Bake the cookie bars for 30 minutes, or until the top of the bars are light golden brown and the edges start to pull away from the pan.
Cool the bars on a wire rack to room temperature, then refrigerate for about 30 minutes to allow the caramel layer to set. DO NOT TRY TO CUT BEFORE THEY'RE COOL, it will turn into a huge gooey mess. Cut into squares and serve. Store leftovers in an airtight container at room temperature.