Lemon Squares

It is important that both the filling and the crust be warm when assembling the bars in step 4; this ensures that the lemon curd will cook through evenly. Be sure to zest the lemons before juicing them.

CRUST
1 1/4 cups all-purpose flour
1/2 cup confectioners' sugar
1/2 teaspoon salt
8 tablespoons (1 stick) unsalted butter, cut into 8 pieces and softened

FILLING
2 large eggs plus 7 large egg yolks
1 cup plus 2 tablespoons granulated sugar
1/4 cup grated fresh lemon zest (from approximately 4 lemons)
2/3 cup fresh lemon juice (from approximately 4 lemons (Note: if using Meyer lemons, which are smaller, you will need 8 lemons)
pinch salt
4 tablespoons unsalted butter, cut into 4 pieces
3 tablespoons heavy cream

confectioners' sugar for dusting

1. Adjust an oven rack to the middle position, and heat the oven to 350 degrees. Line an 8-inch square baking pan with aluminum foil (use 2 pieces and lay opposite of one another to form a sling) and grease the foil.

2. FOR THE CRUST: Process the flour, confectioners' sugar, and salt together in a food processor to combine, about 3 pulses. Sprinkle the butter over the top and pulse until the mixture is pale yellow and has the texture of coarse sand, about 8 pulses. Sprinkle the mixture into the prepared pan and press into an even layer with the bottom of a glass. Bake the crust until fragrant and beginning to brown, about 20 minutes.

3. FOR THE FILLING: While the crust bakes, whisk the eggs and egg yolks together in a medium sauce pan. Whisk in the granulated sugar until combined, then whisk in the lemon zest, lemon juice, and salt. Add the butter and cook over medium heat, stirring constantly, until the mixture thickens slightly and registers 170 degrees on an instant read thermometer, about 5 minutes. Strain the mixture immediately into a bowl (to remove the zest), and stir in the cream.

4. Pour the filling over the warm crust. Bake the squares until the filling is shiny and opaque and the center jiggles slightly when shaken, about 15 minutes (rotating the pan halfway through baking).

5. Let the bars cool completely in the pan, set on a wire rack, about 2 hours. Remove the bars from the pan by lifting the foil. Cut into 16 squares, and dust with confectioners' sugar before serving.