Cookie Love’s Dream Bars

Ingredients

4 ounces bittersweet chocolate (64 percent to 66 percent cacao), melted

1 cup (8 ounces) unsalted butter, at room temperature

½ cup granulated sugar

1 tablespoon water

1 teaspoon vanilla

2 extra-large eggs, separated, at room temperature

2 cups unbleached all-purpose flour

1 teaspoon baking powder

1 teaspoon baking soda

1 teaspoon kosher salt

1 cup firmly packed dark brown sugar

Directions

Invert a baking sheet; spray it with nonstick cooking spray. Line the top with parchment paper. With an offset spatula, spread the melted chocolate evenly across the parchment. Place the baking sheet in the freezer until firm, about 30 minutes.

Meanwhile, lightly coat a 9-by-13-inch rimmed baking pan (a quarter sheet pan) or glass baking dish with nonstick cooking spray; line with parchment paper, leaving 1 inch of overhang on the long sides.

In the bowl of a stand mixer fitted with the paddle attachment, mix the butter on medium speed, 5-10 seconds. Add the granulated sugar; beat until mixture is aerated, 3-4 minutes. Scrape the sides and bottom of the bowl with a rubber spatula to bring the batter together.

Add the water and vanilla to the egg yolks. On medium speed, add the yolks, one at a time, mixing briefly until the batter resembles cottage cheese, about 5 seconds per yolk. Scrape the sides and bottom of the bowl to bring the batter together. Mix on medium speed to make nearly homogeneous, 20-30 seconds.

In a separate bowl, whisk together the flour, baking powder, baking soda and salt.

Add the flour mixture all at once; mix on low speed until the dough just comes together but still looks shaggy, about 30 seconds. Do not overmix. With a plastic bench scraper, bring the dough completely together by hand.

Transfer the dough to the prepared pan. Using a rubber spatula and then your fingertips, press the dough into the corners of the pan and smooth the surface.

Remove the chocolate from the freezer; break it up into shards. Scatter the chocolate shards across the surface of the dough; press into the dough. Cover the top with plastic wrap, pressing down through the plastic to smooth the top. Refrigerate until the dough is set, at least 20 minutes or overnight. (If refrigerating the dough overnight, refrigerate the egg whites as well, letting them come to room temperature before proceeding with the meringue.)

Heat the oven to 350 degrees.

In a stand mixer fitted with the whisk attachment, whip the egg whites and a pinch of kosher salt on medium speed until frothy, about 45 seconds. Add the brown sugar; whip on medium-high speed until shiny peaks form and the meringue holds its shape, 2-3 minutes. Spread the meringue evenly over the chilled dough.

Bake, rotating the pan halfway through the baking process, until the meringue resembles a lightly toasted marshmallow, 23-25 minutes. It will start to crack on the sides but should still be slightly soft in the center, and the bottom layer should be cooked through but still pale, not golden brown. (Do not overbake or the shortbread will be too crumbly to cut.) Cool completely in the pan. Once cool, refrigerate until chilled.

Lift the bars out of the pan using the parchment handles; transfer to a cutting board. Cut the bars lengthwise into 3 strips. Cut the bars crosswise into 10 strips to make small, rectangular bars. Serve the bars at room temperature.