Ingredients

12 tablespoons (1 1/2 sticks), plus 1 tablespoon cold unsalted butter
1 3/4 cups plus 3 tablespoons all-purpose flour
2/3 cup confectioners' sugar, plus more for garnish
1/4 cup cornstarch
3/4 teaspoon salt plus a pinch
4 eggs, lightly beaten
1 1/3 cups granulated sugar
1 1/2 teaspoons lemon zest
2/3 cup fresh lemon juice, strained
1/4 cup whole milk
2 tablespoons limoncello, or other lemon-flavored liqueur, optional

Directions

Lightly
butter a 9 by 13-inch baking dish with 2 teaspoons of the butter and line with 1 sheet of parchment or waxed
paper. Butter the top of this sheet of paper with 1 teaspoon of the remaining butter and then lay a second
sheet of parchment or waxed paper crosswise over the first sheet. The parchment should be cut large enough so

that the sides are even with the top of the baking dish; this extra paper will function as handles to help you
remove the lemon squares from the pan later. Set pan aside.

In a large bowl combine 1 3/4 cups of the flour, 2/3 cup of the confectioners' sugar, the cornstarch, and 3/4
teaspoon of the salt and mix thoroughly. Cut the remaining 12 tablespoons of butter into small pieces and add
to the flour mixture. Using your hands, 2 forks, or a pastry blender, work the butter into the flour mixture
until the mixture resembles coarse meal. Transfer the butter-flour mixture to the prepared baking dish and
press into an even 1/4-inch layer along the bottom and partly up the sides of the pan. Refrigerate for 30
minutes.

While the crust is chilling, preheat the oven to 350 degrees F.

Bake the crust until golden brown, about 20 to 25 minutes.

While the crust is baking, assemble the filling by combining the eggs, granulated sugar, flour, and lemon zest
in a medium bowl and whisking until smooth. Stir in lemon juice, milk, limoncello, and remaining pinch of salt
and mix well.

When the crust is golden brown, remove it from the oven and reduce the oven temperature to 325 degrees F. Stir

the lemon mixture again, then pour onto the warm crust. Bake until the filling is set, about 20 minutes.
Transfer to a wire rack to cool completely. Grasp the waxed paper that lines the 2 longest sides of the baking
dish and remove the bars from the pan by pulling up gently. The entire dessert should easily dislodge and come
away from the pan. Transfer to a cutting board and, using a clean knife, cut into squares, wiping knife after
each cut. Place a small amount of confectioners' sugar into a small sieve, and sprinkle the bars with the
sugar. Serve immediately, or refrigerate, wrapped with plastic wrap, up to 2 days, until ready to serve.