Recipe adapted from “The Art and Soul of Baking,” by Sur La Table with Cindy Mushet (Andrews McMeel Publishing). Makes 36 squares.
Ingredients
For shortcrust dough:
1 1/4 cups unbleached all-purpose flour
1/4 cup sugar
1/4 teaspoon salt
1 stick cold unsalted butter, cut into 1/2-inch pieces
2 large egg yolks
2 teaspoons pure vanilla extract
1 to 3 teaspoons water
For filling:
4 large eggs
2 cups sugar
5 tablespoons unbleached all-purpose flour
2/3 cup strained freshly squeezed lemon juice
Confectioners’ sugar, for dusting
Directions
Make shortcrust dough: Place the flour, sugar and salt in the bowl of a food processor. Pulse 5 times. Add the cold butter pieces and pulse 6-8 times, just until the butter is the size of large peas. In a small bowl, whisk together the egg yolks, vanilla and 1 teaspoon water. Add to the butter mixture, then process just until the dough begins to form small clumps, 5 to 10 seconds. Do not let the dough form a ball. Test by squeezing a handful of clumps — when you open your hand, they should hold together. If they are crumbly and fall apart, sprinkle 1 teaspoon water over the dough and pulse several times, then test again.
Preheat the oven to 350 degrees. Line a 9-inch square cake pan with foil across the bottom and up all four sides, then lightly coat with oil. Press dough into an even layer across the bottom of the pan. Chill 30 minutes. Bake the chilled crust for 35 minutes or until golden brown. Transfer to a rack and allow to cool. Reduce the oven temperature to 300.
Make filling: Whisk the eggs and sugar together in a medium bowl. Whisk in the flour until there are no lumps. Whisk in the lemon juice. Pour the filling over the crust. Bake for 40-50 minutes or until the filling is set and does not jiggle when you tap the side of the pan. Transfer to a rack to cool.
Use the foil to lift the cookies out of the pan. Cut into squares. Dust with confectioners’ sugar.
