Steam-Baked Lemon Meringue Pie Bars

Line an 8-inch square cake pan (not a glass baking pan) with two sheets of heavy duty foil to form a sling. Grease with nonstick oil spray.

In a medium bowl, whisk together the all-purpose flour, whole wheat flour, sugar, and salt. Add the butter and stir with a rubber spatula until the mixture forms a rough, crumbly dough. Transfer to the prepared pan and press into an even layer.

Transfer to the oven and bake until golden brown and set, 20 to 25 minutes. Remove from the oven.

Open the oven door for 1 minute to help it cool down quickly.

While the oven adjusts, make the filling. Sift the flour into a large bowl. Whisk in the sugar and salt. In a small bowl, beat together the whole eggs and yolks. Add to the flour mixture and whisk until smooth. Whisk in the lemon juice, cream, and zest until smooth.

Pour the filling onto the crust. (It’s okay if the crust is still a bit warm.) Tap on the counter to remove any air bubbles.

Transfer to the oven and bake until the filling is just set with a slight wiggle, 30 to 45 minutes.

Remove from the oven and let cool completely in the pan, 1 to 1 ½ hours.

Once the bars are cool, make the meringue. Whisk together the sugar, egg whites, and cream of tartar in the bowl of a stand mixer. Add about 1 inch of water to a small saucepan. Bring to a simmer over high heat, then reduce the heat to low to maintain the simmer. Place the mixer bowl over the water in the pot, making sure that it is not touching the water. Cook, whisking frequently, until the sugar is dissolved, the mixture is steaming, and the mixture registers 165°F (74°C), about 5 minutes. (If the temperature of the egg mixture stops rising, you can increase the heat under the pot to medium-low.)

Transfer the bowl to the mixer and attach the whisk. Turn the mixer on and gradually increase to high speed. Beat on high until the mixture forms very stiff peaks, about 3 minutes.

Use the sling to remove the lemon bars from the pan. Place on a cutting board and slice into 16 even squares, wiping the knife clean between each cut. Pipe meringue on top of each square. If desired, use a torch to brown the meringue. Serve at room temperature or chill until cold before serving.