Chocolate Dulce de Leche Bars

Directions

1. 1.

   Preheat oven to 375°F with rack in middle. Butter a shallow 9- to 9 1/2-inch square baking pan (1 to 1 1/2 inches deep). Line bottom and 2 sides with parchment paper, leaving an overhang. Butter parchment.

2. 2.

   Blend together butter, brown sugar, vanilla, and salt in a bowl with a fork. Sift in flour and blend with fork until a soft dough forms.

3. 3.

   Spread dough evenly in baking pan using an offset spatula or back of a spoon, then prick all over with fork.

4. 4.

   Bake until golden, 15 to 20 minutes, then cool completely in pan on a rack, about 30 minutes.

5. 5.

   Bring cream and dulce de leche to a simmer in a small heavy saucepan, stirring with a wooden spoon until dulce de leche has dissolved.

6. 6.

   Whisk together yolks in a bowl, then slowly whisk in hot cream mixture. Return to pan and cook over medium heat, stirring constantly, until pan is visible in tracks of spoon and mixture registers 170°F on an instant-read thermometer. Remove from heat and whisk in chocolate until melted.

7. 7.

   Pour chocolate mixture over cooled shortbread and chill, uncovered, until cold and set, about 2 hours.

8. 8.

   Run a small knife around edges to loosen, then transfer to a cutting board using parchment. Cut with a hot clean knife (dip in hot water and wipe clean between cuts) into 24 bars. Chill until ready to serve.