Chocolate-Caramel Shortbread Bars

Directions

1. 1
   Beat butter in a medium bowl with an electric mixer until creamy. Beat in powdered sugar and 1 teaspoon vanilla extract. Combine flour and salt in a medium bowl; gradually beat into butter mixture.
2. 2
   Press dough into a greased, aluminum foil-lined 9- x 9-inch baking pan. Bake at 350° for 23 to 25 minutes. Set aside.
3. 3
   Combine sugar, 1/2 cup heavy cream, corn syrup, and butter in a 2-quart heavy pot. Cook over medium-low heat, stirring often, until butter melts and sugar dissolves. Increase heat to medium, and bring to a boil. Boil, without stirring, until mixture reaches 238° (just past soft ball stage) on a candy thermometer.
4. 4
   Combine remaining 1/2 cup cream and remaining 1 teaspoon vanilla extract; carefully pour into sugar mixture. (Mixture will bubble.) Boil until mixture returns to 238°. Pour over shortbread crust. Let stand at room temperature or refrigerate until caramel is firm.
5. 5
   Pour Chocolate Ganache over caramel, smoothing with an offset spatula. Sprinkle with sea salt. Let stand in a cool place until chocolate is firm. Cut into bars.