Why It Works
- Blitzing the ingredients in a food processor coats the flour in fat, minimizing gluten development for a light and tender crust.
- Cooking on the stovetop allows for precise control of the custard's final temperature, preventing soft or runny bars.
- Straining removes lumpy bits, keeping the custard silky-smooth.
- A brief stint in the oven smooths the custard into an even layer with a glossy finish.
These lemon bars are something of a cross between lemon curd and lemon meringue pie, soft and rich with egg yolks, but thick enough to slice into neat squares—no cornstarch required. That keeps the custard translucent and bright, as refreshing as a cold glass of lemonade. Serve with a simple dusting of powdered sugar, or dress them up with Lemon Chantilly and Crispy Citrus-Candied Pistachios.
- For the Crust:
- 4 1/2 ounces (1 cup; 130g) all-purpose flour
- 2 ounces (1/2 cup; 60g) powdered sugar, preferably organic
- 1/4 teaspoon (1g) Diamond Crystal kosher salt; for table salt, use the same weight or half as much by volume
- 1/8 ounce (1 tablespoon; 4g) freshly grated lemon zest
- 4 ounces (1 stick; 115g) cold unsalted butter, cut into 1/4-inch dice
- For the Custard:
- 3 large eggs, cold
- 4 3/4 ounces (1/2 cup; 135g) egg yolks, from about 8 large eggs
- 9 1/2 ounces (1 1/3 cups; 270g) granulated sugar
- Pinch of kosher salt
- 1/4 ounce (1 packed tablespoon; 8g) freshly grated lemon zest
- 11 ounces (1 1/3 cups; 310g) lemon juice, from about 8 large lemons (see note)
- For Garnishing:
- 2 ounces (1/2 cup; 55g) powdered sugar (optional)
- 6 ounces (1 cup; 170g) Lemon Chantilly (optional)
- 5 ounces (1 cup; 140g) Crispy Citrus-Candied Pistachios (optional)
For the Crust: Adjust oven rack to middle position, preheat oven to 350°F, and line an 8- by 8- by 2-inch anodized-aluminum baking pan with a piece of parchment paper long enough to overhang the pan's edges. Combine flour, powdered sugar, salt, lemon zest, and butter in the bowl of a food processor; pulse to form a dry but pebbly meal, about twelve 1-second pulses. Scatter into the prepared baking pan, press into an even layer, and bake until pale gold and firm, about 30 minutes. Use hot or set aside until needed, up to 48 hours at room temperature if tightly covered.
For the Custard: Combine whole eggs, yolks, sugar, salt, and lemon zest in a 3-quart stainless steel saucepan, then whisk in lemon juice. Cook over low heat, stirring constantly but not vigorously, until warm to the touch, about 3 minutes. Increase heat to medium-low and continue cooking and stirring until thick and steaming-hot (custard should register 170°F on an instant-read thermometer), about 8 minutes. Immediately strain into the prepared crust, smooth into an even layer, and cover with aluminum foil. Bake until smooth and firm, about 10 minutes. Remove foil and cool to room temperature, then re-cover and refrigerate until cold and firm, about 1 hour.
To Serve: Loosen chilled custard from sides of pan with a bench or butter knife, then carefully tug loose and lift using overhanging parchment and transfer to a cutting board. Cut into 16 two-inch squares, rinsing the knife clean between each slice. Serve plain, lightly dusted with powdered sugar, or topped with Lemon Chantilly and Crispy Citrus-Candied Pistachios. Store up to 1 week in an airtight container.
This recipe works best with the bright acidity of traditional supermarket lemons, not mellow Meyers, in order to balance the sweetness of the custard. Be sure to save the leftover rinds, which form the basis of my Fresh Lemon Syrup.