Preheat the oven to 325 degrees. Butter a 9 x 13-inch pan or spray with nonstick cooking spray, and line the bottom with a piece of parchment paper cut so that it fits cleanly in the pan but hangs over the two long sides (you will use this to lift out the squares once they are baked and cooled).
In a food processor combine the flour, granulated sugar, and salt. Add the butter and pulse until the mixture resembles coarse corn,eal (alternately, you can cut in the butter into the flour mixture in a bowl using two knives, a pastry cutter, or your fingers). Transfer the mixture to the pan, and press the mixture evenly into the bottom. Bake for 15 to 18 minutes until golden and a bit firm to the touch.
Meanwhile, in a medium bowl, combine the eggs and granulated sugar, and whisk or beat with an electric mixer until smooth. Beat in the lemon juice and cream, and then beat in the flour, until very smooth. When the crust is golden and set, pour in the filling, return the pan to the oven, and bake for 25 to 35 minutes. until it doesn’t jiggle at all when you gently shake the pan. Let cool completely on a wire rack to room temperature.
Place the 1/4 cup confectioners’ sugar into a small sieve and dust it over the lemon bars just before serving. Run a knife around the edge of the pan, and cut the bars into 20 squares. Remove the bars with a spatula, or carefully use the overhanging edges of the parchment to smoothly lift out the lemon bars.
Notes
The filling in these squares, or bars, is a bit tart (I don’t see the point of too-sweet lemon squares), but not confrontational. Adding a couple of tablespoons of heavy cream offers a creamier, silkier texture to the filling and a smoother citrus experience.Sometimes lemon zest is added to the filling, and while I love the extra burst of citrus, I’m more in love with a super smooth filling, so I skip it, but you can add a teaspoon or so of zest if you like.