Active Time

　　30 min

　　Total Time

　　3 1/4 hr

　　Fudgy cookies go Latin with an infusion of dulce de leche, a sweet milk caramel similar to cajeta and arequipe. These cool treats are happily portable on their crisp shortbread crusts.

　　

Ingredients

Makes 24 bars

　　

For shortbread crust:

1 stick unsalted butter, softened

　　1/3 cup packed light brown sugar

　　1/2 teaspoon pure vanilla extract

　　1/2 teaspoon salt

　　1 cup all-purpose flour

　　

For chocolate dulce de leche:

1 cup heavy cream

　　1 cup dulce de leche

　　4 large egg yolks

　　5 ounces 60%-cacao bittersweet chocolate, finely chopped (preferably in a food processor)

　　

Make shortbread crust:

Step 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.

　　

Step 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.

　　

Step 3

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

　　

Step 4

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

　　

Make chocolate dulce de leche:

Step 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.

　　

Step 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.

　　

Make bars:

Step 7

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

　　

Step 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.

　　Cooks' note:

　　Chocolate dulce de leche bars can be chilled in an airtight container up to 1 day.