I've been holding out on you. I know, I'm sorry. I don't even know why — because these lemon bars ... oh man, they are meant to be shared. In fact, keeping them to yourself would be very dangerous. The truth is that I've been making this lemon curd recipe on its own for years, and I've been tinkering with my favorite shortbread recipe for years. Now, finally, I've had the presence of mind to bring them together. No need to thank me — you're welcome.
You're really getting a 3-for-1 deal with this recipe. The curd on its own is fantastic on toast or squidged between cookies. Or ... you know, spooned directly from the jar. The shortbread is the perfect mid-morning nibble with a second cup of tea. And combined? Oh, mama. Yes. Serve these at your next picnic and you'll be a hero.
I'll grant you that these lemon bars are a little fussier than many other lemon bar recipes. Rather than pouring the lemon mixture directly onto the shortbread, you first cook it on the stovetop until thickened. This two-step process results in a lemon curd layer of surpassing silkiness, but one that also cuts cleanly and can hold up outside of refrigeration for a while. I still think they're best while ice-cold from the fridge, but the way the curd softens slightly after a little time on the table is its own kind of delight.
Oh, one more point in favor of lemon bars: you can make them ahead. In fact, you should make them ahead. They need a little time to set up, and like I said, lemon bars chilled from the fridge on a hot day are a beautiful thing.
Make these soon. I hope you love them as much as I do. Don't forget to share.
Heavenly Lemon Bars with Almond Shortbread Crust
Makes 9 large or 16 small squares
For the crust:
8 tablespoons (1 stick) unsalted butter, softened and cut into chunks
1/2 cup powdered sugar
1 cup all-purpose flour
3/4 cup almond meal (or more flour)
1/2 teaspoon salt
For the lemon curd:
4 large eggs
4 large egg yolks
1 cup granulated sugar
Zest from 5 to 6 lemons
3/4 cup fresh-squeezed lemon juice (from 5 to 6 lemons)
1/4 teaspoon salt
8 tablespoons (1 stick) unsalted butter, softened and cut into cubes
Powdered sugar, for dusting
Heat the oven to 350°F with a rack in the middle position. Line an 8x8-inch baking dish with parchment, letting the excess parchment hang over the sides of the pan.
First, prepare the shortbread crust. Beat together the butter and powdered sugar in a stand mixer (or with a hand mixer) on medium-high speed until they are completely combined, turn pale yellow, and resemble creamy frosting. Stop the mixer and scrape down the sides of the bowl as needed while mixing.
Add the all-purpose flour, almond flour, and salt to the bowl. Beat on low speed just until all the flour is incorporated and the mixture comes together into a dough. The dough will seem fairly crumbly, but should hold together when squished in your hand.
Press the dough into the baking dish. Use the bottom of a cup to make sure the layer is as compacted as possible and in an even layer. Prick with a fork all over. Bake for 20 to 25 minutes, until the edges of the shortbread turn golden-brown.
While the shortbread crust is baking, prepare the lemon curd. Whisk together the eggs, yolks, and sugar in a small (2-quart) saucepan, then whisk in the lemon zest, lemon juice, and salt to form a smooth, liquidy mixture. Set a small strainer over a mixing bowl and place next to the stove.
Place the pan with the lemon mixture over medium heat. Stir, gently but continuously, until the mixture thickens enough to coat the back of a spoon and registers about 155°F on an instant-read thermometer; this should take 8 to 10 minutes. Be sure to scrape the bottom and edges of the pan as you stir. If you notice the mixture starting to coagulate and clump up, immediately remove the pan from heat.
Strain the lemon curd into the bowl, removing the zest and any clumps from the curd. While the curd is still warm, stir in the butter. Stir until the butter is completely melted.
When the shortbread crust is ready, remove it from the oven and pour the curd over top. (It's okay if one is finished before the other, though ideally, they will finish at close to the same time.) Put the pan back in the oven and bake at 350°F until the edges of the curd are set, but the middle is still jiggly, 10 to 15 minutes.
Cool completely on the counter, and then cover and refrigerate for at least 4 hours (or overnight). To slice, run a knife around the edge of the bars and then lift them onto a cutting board using the flaps of parchment paper. Use a chef's knife to cut straight down into bars; wipe the knife clean between cuts. Bars will keep refrigerated for several days.
Lemon curd on its own: To make just the lemon curd, cook it on the stovetop, strain, and stir in the butter as directed. No need to bake. Transfer the curd to a lidded container and refrigerate. Eat within a week.
Shortbread on its own: To make just the shortbread, prepare the dough and bake as directed, but bake an extra 5 to 10 minutes until the top of the shortbread is also slightly golden. Cool completely, transfer to a cutting board, and cut into rectangles or squares.