Lemon Squares

Directions

1. 1
   Take a few bits of the butter and, using your hands, grease an 18 x 13-inch (half-sheet size) rimmed baking sheet.
2. 2
   To make the crust, in the work bowl of a food processor fitted with the metal blade, combine 3 cups of the flour, the 3/4 cup of confectioners sugar, and half of the salt; pulse until well combined.
3. 3
   Add the remaining butter and pulse until the mixture starts to pull away from the sides of the bowl.
4. 4
   Transfer to the prepared baking sheet and, using your fingers, press into the pan.
5. 5
   To ensure that the dough is a smooth, uniform layer, cover with a sheet of plastic wrap, then, using the back of a spoon, spread the dough evenly in the pan.
6. 6
   Chill in the refrigerator until firm, about 30 minutes.
7. 7
   Preheat the oven to 350F.
8. 8
   Bake the chilled dough until golden brown, rotating once, about 30 minutes; remove to a rack and leave the oven on.
9. 9
   Meanwhile, to make the filling, in the work bowl of the food processor (no need to worry about residual dough), combine the remaining 2/3 cup of flour, the granulated sugar, the remaining pinch of salt, eggs, grated lemon zest, and lemon juice.
10. 10
    To assemble, pour the filling on top of the still-warm crust.
11. 11
    Bake until set and just beginning to color, 30 to 35 minutes.
12. 12
    Transfer to a rack to cool completely, about 2 hours.
13. 13
    Sift over additional confectioners sugar.
14. 14
    Slice into squares and serve.