Let's just get this out of the way — I really love lemon bars. Sure, I love chocolate chip cookies and a very good brownie as much as the next person, but lemon bars light me up like a little kid; their eye-catching brightness and promise of a sweet pucker always reel me in. This lemon bar is what I consider the ideal, with a buttery shortbread crust that is sturdy but tender enough to bite through and a thick and luscious filling with a balance of sweetness and tangy lemon brightness.
A solid recipe for this beloved bakery-style treat remained elusive to me for many years, as I often attempted to turn lemon curd into bars without success. As it turns out, there are just a few key steps to making the very best lemon bars at home, including a secret ingredient for a soft and sturdy crust, smart timing for filling the crust, and a lemon filling (not curd) that bakes up with all the brightness I was searching for. Here's how to make the very best classic lemon bars at home.
Everything You Need to Know About Making Lemon Bars
It's helpful to know right away that you'll need three lemons to make these bars. With a triple dose of lemon flavor — zest in both the crust and filling and the fresh juice in the filing — zest the lemons first, and then juice them. You'll have more than enough zest for both the crust and filling, and will avoid the awkward zesting of half a juiced lemon.
The Secret Ingredient for Better Lemon Bars
Unlike other lemon bar recipes, powdered sugar isn't just a garnish for these bars — it lends its cornstarch-enhanced sweetening powder to both the crust and the filling. You'll also need some pantry basics like granulated sugar, all-purpose flour, eggs, butter, and salt.
Step-by-Step Directions for Making Classic Lemon Bars
- Use an 11x7-inch glass baking dish: And make sure it is lined with parchment paper that overhangs on either side. This will make removing the finished lemon bars a breeze.
- Use the food processor for a delicate crumb: Not only is this much easier than mixing by hand, but it also makes for a more delicate crumb in the crust.
- Press in the pan for a thin crust: The crust should be tightly pressed into the pan the same way you might press a graham cracker or cookie crust into a baking dish. The more compact and thin you can get the crust, the better — so use a measuring spoon or the bottom of a heavy glass to help press and smooth the crust.
- Parbake the crust to prevent sogginess: The shortbread crust has a longer baking time than the filling, so it needs to go into the oven for about 20 minutes ahead of the lemon filling. You also want to add the lemon filling to the crust while the crust is still warm. Both parbaking and adding the filling to the warm crust prevent a soggy crust.
- Cool before cutting for sharp edges: There will be some carryover cooking of the lemon filling after baking, and the crust needs to cool completely to be sturdy enough for eating. Cool the lemon bars in the pan for about 30 minutes and then move them to a cooling rack (use that parchment paper sling!) to cool completely.
How to Make a Very Good Shortbread Crust for Lemon Bars
A great crust is paramount to enjoying lemon bars. The crust must be sturdy and supple. Three keys will easily get you the best possible version.
- Use a combination of granulated sugar and powdered sugar: The small amount of cornstarch that comes from the powdered sugar makes the crust more tender.
- Use cold butter and a food processor to make the crust: Similar to making a pie dough, cold butter will make for a more tender shortbread crust. Using a food processor to mix the crust not only makes mixing faster, but also keeps the butter cool.
- Parbake the crust: Baking the crust without the filling gives it a head start on baking and browning, yes, but it also ensures that the crust sets without absorbing too much moisture from the lemon filling.
How to Make the Best Lemon Filling for Lemon Bars
I long believed that the best lemon bars were filled with lemon curd, that is a lemon mixture cooked once to thicken it and another time to make the bar, but I was always disappointed by a dry filling without much flavor. Instead the best way to fill lemon bars is to make a lemon-like custard with lemon juice, eggs, and sugar.
Using powdered sugar in addition to granulated sugar makes for a creamier, more pudding-like filling. The tiny amount of cornstarch in the powdered sugar helps to gently thicken it as it cools.
Standard lemons make for classic lemons bars, but if you happen to have an excess of Meyer lemons, limes, or Seville oranges, you can substitute them one for one with the lemon zest and lemon juice called for here.
Other citrus like navel oranges, clementines, or cara cara oranges should be used in partnership with lemon. For example, use half orange and half lemon for both the zest and juice called for here. This 50/50 mix keeps the bars from being too sweet and ensures they set properly.
How To Make Lemon Bars
What You Need
For the crust:
Cooking spray or butter
1 cup all-purpose flour
1/4 cup granulated sugar
1/4 cup powdered sugar
1 teaspoon finely grated lemon zest
1/4 teaspoon kosher salt
8 tablespoons unsalted butter, cubed and chilled
For the filling:
4 large eggs
1 large egg yolk
1 cup granulated sugar
2 tablespoons powdered sugar, plus more for dusting
2 tablespoons finely grated lemon zest (from 2 lemons)
1/4 teaspoon kosher salt
1/2 cup freshly squeezed lemon juice (from 2 to 3 lemons)
1/4 cup all-purpose flour
11x7-inch glass baking dish
Measuring cups and spoons
Fine mesh strainer
- Heat the oven and prepare the baking dish: Arrange a rack in the middle of the oven and heat to 325°F. Lightly coat an 11x7-inch baking glass dish with cooking spray or butter. Line the dish with a parchment paper sling, leaving an overhang of about 2 inches on each long side; set aside.
- Make the crust: Place the flour, granulated sugar, powdered sugar, zest, and salt in the bowl of a food processor fitted with the blade attachment. Pulse 5 times to combine. Add the butter and pulse until the mixture looks like coarse crumbs.
Press the crust in and chill: Pour the crust mixture into the prepared baking dish. Use the bottom of a measuring cup or your fingers to press the crumbs into an even layer. Refrigerate for 15 minutes.
Parbake the crust: Bake the crust until light golden-brown, 25 to 30 minutes.
- Make the filling: Whisk the whole eggs, egg yolk, granulated sugar, powdered sugar, zest, and salt together in a large bowl. Whisk in the lemon juice, and then the flour, until combined.
- Pour the filling onto crust: Remove the parbaked crust from the oven. Pour the lemon filling onto the warm crust.
- Bake the lemon bars: Return the pan to the oven and bake until light brown around the edges and the top appears relatively dry, 15 to 20 minutes. Cool completely on a wire rack before cutting.
- Dust with powdered sugar: Remove the lemon bars from the pan using the parchment sling. Use a fine-mesh strainer to generously dust the bars with powdered sugar.
Cut the lemon bars: Place on a cutting board and cut into 12 pieces. Dust with more powdered sugar, if desired, before serving.
- Storage: Lemon bars may be covered and refrigerated for up to 3 days ,but are best eaten within 24 hours.