Shortbread Crust
2 cups all-purpose flour
1/2 cup light brown sugar
1/4 cup cornstarch
1/2 teaspoon Kosher salt
1 cup unsalted butter, cold and cut into cubes
2 tablespoons cold water
2 egg yolks

Caramel
2 14 oz. cans sweetened condensed milk
1 cup light brown sugar
3/4 cup unsalted butter, cut into cubes
1/4 cup corn syrup
2 teaspoons vanilla extract

Salted Chocolate
1 12 oz. bag chocolate (I would have preferred semisweet, but I only had milk chocolate, so I used that and it was great, just sweet)
1 tablespoon fleur de sel, for topping