Eyes light up at the sight of these tart and refreshing favorites. A soft, puckery lemon filling atop a vanilla-scented short crust is just the ticket after a rich winter meal, and it is also a refreshing treat on a hot summer day. Okay, okay, it’s great anytime. Surprisingly easy to make, these bars deliver a lot of satisfaction for the amount of elbow grease invested. Of course, lemon is the classic, but you could substitute lime juice as well. Or, for a more exotic version, try an equal amount of passion fruit juice instead of the lemon juice.
For the crust:
For the filling:
For the crust:
To mix the dough using a food processor: Place the flour, sugar, and salt in the bowl of a food processor. Pulse 5 times to blend. Add the cold butter pieces and pulse 6-8 times, just until the butter is the size of large peas. In the 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, 5-10 seconds. Do not let the dough form a ball. Test the dough 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. Repeat, if necessary.
To mix the dough by hand: Place the flour, sugar, and salt in the medium bowl and blend well with a whisk. Add the cold butter pieces and toss until they are lightly coated with the flour. Use the pastry blender or your fingertips to cut the butter into the flour until the mixture resembles bread crumbs or crushed crackers. If at any time during this process the butter softens and becomes warm, place the bowl in the freezer for 10 minutes before continuing. In the small bowl, whisk together the egg yolks, vanilla, and 1 teaspoon water. Add to the dry ingredients and toss between your fingertips or with a fork 20-30 times to evenly distribute the moisture. The dough will still look very crumbly, but if the mixture is squeezed in your hand, it should hold together. If not, sprinkle another teaspoon of water over the top and toss to blend. Repeat, if necessary.
Preheat the oven to 350 degrees and position an oven rack in the center. Line a 9-inch square baking pan with foil across the bottom and up all 4 sides, then lightly coat with melted butter, oil, or high-heat canola-oil spray.
With a spatula, scrape the dough into the prepared pan and press it into an even layer across the bottom of the pan. Chill for 30 minutes.
Bake the chilled crust for 35-45 minutes, until golden brown. Transfer to a rack and allow to cool for 20 minutes. Reduce the oven temperature to 300 degrees.
For the filling:
Whisk the eggs and granulated 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 50-60 minutes, until the filling is set and does not jiggle when you tap the side of the pan. Transfer to a rack to cool completely. When cool, refrigerate for 1 hour.
To serve, grasp the foil and lift the cookies out of the pan. Set them on a cutting surface. Gently peel back the foil, using the tip of a thin knife or a small spatula to help separate the bars from the foil if necessary. Cut into 1 ½-inch squares and transfer to a serving plate or storage container. Just before serving, use a fine-mesh strainer to dust confectioners’ sugar over the tops, if using. (Wait until the last minute to do this or the confectioners’ sugar will soak into the filling and look blotchy.)