Why It Works
- Pouring melted butter over the dry ingredients evenly coats the flour particles with fat, resulting in buttery, tender shortbread that melts in your mouth.
- Topping the bars with an Italian meringue—which involves pouring a hot sugar syrup into whipping egg whites—cooks the whites, resulting in a stable meringue that’s unlikely to weep as the bars sit.
I had my first amaretto sour eight years ago, when my husband, who I was dating at the time, shook up the cocktail for me. Made with fresh lemon juice, amaretto, bourbon, simple syrup, and an egg white—all shaken with ice until cold and frothy—the drink was bright, fruity, and pleasantly sour. It was a delightful contrast to the rum and Coke, my go-to drink at the time. The egg-white foam sat on top of the beverage, forming a distinctly fluffy layer on top, and an Amarena cherry left a rich, syrupy trail towards the bottom of the glass. The drink reminded me of my favorite lemon bars: punchy enough to make you pucker, with just enough sugar to balance its tartness.
With the holiday season upon us, I decided it was finally time to use my favorite drink as a blueprint for a fun new addition to my regular roster of cookies. Cue the amaretto sour lemon bar: a sharp amaretto-spiked lemon curd baked atop buttery shortbread topped with swoops of pillowy Italian meringue and an Amarena cherry.
Serious Eats / Vy Tran
4 Key Techniques for the Best Amaretto Sour Lemon Bars
Use melted butter for an easier, faster shortbread base. While most lemon bars use a cold butter shortbread as their base, those doughs are often fussy to handle or require significant chilling time. As Genevieve does in her shortbread, I also chose to use melted butter instead of cold butter to make my shortbread base, a much easier method that produces similarly delicious results. The melted butter coats the flour particles with fat, which minimizes gluten development and keeps the cookie crust tender.
Use extra yolks and cook the curd to a slightly higher temperature than normal for a rich, stable curd. In addition to three whole eggs, I use three egg yolks, which give the curd additional richness and flavor. (The egg whites get used in the meringue, so they don’t go to waste.) It’s essential to cook the curd properly: It may be tempting to stop cooking the curd around 150ºF (66ºC), which is when it begins to thicken, but for a custard that sets into a sliceable texture, I recommend taking the curd to a slightly higher temperature of 170ºF (77ºC), which is in line with what former Serious Eats editor Stella recommends in her recipe for sunny lemon bars. Once the curd hits that temperature, I strain the mixture through a fine-mesh sieve for a silky-smooth filling.
Use an Italian meringue for the most stable topping. The final layer is an Italian meringue. While it’s known to be the fussiest among Swiss, Italian, and French meringues, it’s also the most stable. Pouring a hot sugar syrup into the whipping egg whites cooks them, preventing the meringue from weeping as the bars sit, and also producing a foam that’s sturdy enough to withstand the weight of the Amarena cherries. Though it isn’t necessary, I recommend lightly toasting the meringue—either with a kitchen torch or under the broiler—which turns the bars into a majestic looking dessert reminiscent of lemon meringue pie. (Because it’s difficult to whip a small amount of egg whites, this recipe produces more meringue than you’ll need: Use it to top another pie, tart, or bar, or spread it out onto a foil-lined baking sheet, then lightly pass a kitchen torch over it for a marshmallow-y treat.)
Reach for Amarena cherries. I recommend using rich burgundy Amarena cherries. Unlike Maraschino cherries, Amarena cherries have nuanced sweet and sour notes and are firm and juicy, making them a pleasure to bite into. Placed on each bar, they are the literal cherry on top.
Serious Eats / Vy Tran
Turn Your Favorite Amaretto Cocktail Into a Boozy Holiday Dessert Your Guests Will Never Forget
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160g all-purpose flour (about 5 1/2 ounces; 1 1/4 cups)
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50g granulated sugar (1 3/4 ounces; 1/4 cup)
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1 teaspoon Diamond Crystal kosher salt; for table salt, use half as much by volume
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140g unsalted butter (5 ounces; 10 tablespoons), melted
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275g granulated sugar (9 3/4 ounces; about 1 1/3 cups)
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1/4 teaspoon Diamond Crystal kosher salt; for table salt, use half as much by volume
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3 large eggs
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3 large egg yolks, whites reserved
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2/3 cup (160ml) fresh lemon juice from 5 medium lemons
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1/4 cup (50g) amaretto liqueur (see notes)
For the Meringue:
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150g granulated sugar (5 1/4 ounces; 3/4 cup)
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1/3 cup (80ml) water
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3 large egg whites (from above)
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1/4 teaspoon cream of tartar
To Garnish:
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For the Crust: Adjust oven rack to middle position and preheat to 350°F (175°C). Line an 8- by 8-inch aluminum baking pan with two 8-inch wide strips of parchment long enough to overhang pan’s edges by 2 inches; set aside.
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In a medium mixing bowl, whisk flour, sugar, and salt to combine. Pour melted butter into flour mixture and, using a rubber spatula or dough scraper, incorporate butter into dry ingredients, gently stirring and pressing to combine, until a cohesive dough just forms and no dry bits remain, about 1 minute. (Be careful not to overwork the dough.)
Serious Eats / Vy Tran
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Scrape dough into prepared baking pan and, using an offset spatula or the flat bottom of a glass or measuring cup, press dough into an even layer. Bake until fragrant, firm, and golden, about 25 minutes. Allow shortbread to cool completely in the baking pan, about 30 minutes.
Serious Eats / Vy Tran
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For the Curd: In a medium saucepan, whisk sugar, salt, whole eggs, and yolks to combine. Add lemon juice and amaretto and whisk until smooth. Cook over low heat, using a whisk to stir frequently, until frothy, about 3 minutes. Increase heat to medium and continue cooking, stirring constantly, until curd thickens and registers 170ºF (77ºC) on an instant-read thermometer, about 8 minutes. Using a fine-mesh sieve, immediately strain curd onto the prepared crust. Using an offset spatula, smooth curd into an even layer, and cover pan with aluminum foil. Bake until smooth and just starting to set along the edges, about 10 minutes. Remove foil and cool to room temperature, about 90 minutes. Then cover again with foil and refrigerate until cold and the curd is firm without any jiggle, about 2 hours and up to 5 days.
Serious Eats / Vy Tran
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For the Meringue: In the bowl of a stand mixer fitted with a whisk attachment, combine egg whites and cream of tartar. With the mixer on medium speed, whisk egg whites until soft peaks form, 10 to 13 minutes. (When lifted, there should be gentle peaks that very slowly collapse back into themselves.)
Serious Eats / Vy Tran
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In a small saucepan, combine sugar and water. Bring to a boil and cook until sugar syrup registers 240°F (116°C) on an instant-read or candy thermometer, about 4 minutes.
Serious Eats / Vy Tran
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With the mixer running on medium speed, carefully and slowly drizzle hot sugar syrup into the bowl along the side, avoiding hitting the whisk attachment. Increase speed to high and whip until stiff peaks form and meringue is no longer hot, about 10 minutes.
Serious Eats / Vy Tran
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For Assembling the Bars: Line a rimmed baking sheet with foil. Run an offset spatula or butter knife around edges of baking pan, then carefully lift parchment overhang to gently remove bars. Place bars on a cutting board and, using a sharp knife, cut bars into sixteen 2- by 2-inch squares. (For cleaner cuts, run knife under warm water and dry knife with a clean kitchen towel before portioning each slice.)
Serious Eats / Vy Tran
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Place the cut lemon squares on prepared baking sheet. Spoon a generous dollop of meringue on top of a lemon square and, using the back of the spoon, make an indent just deep enough to hold an Amarena cherry. Repeat with remaining lemon bars. Using a kitchen blowtorch, torch meringue 1 to 2 inches away from surface until evenly browned. (See notes for broiler instructions if you do not own a blowtorch.) Refrigerate until cold, about 30 minutes. Top each bar with a single cherry before serving.
Serious Eats / Vy Tran
Special Equipment
8- by 8-inch aluminum baking pan, medium saucepan, fine-mesh sieve, instant-read thermometer or candy thermometer
Notes
Take note of the ingredients in your amaretto for allergen purposes. Some are derived from almonds but most are made with the kernels of stone fruit such as apricots.
To use the broiler instead of a kitchen torch: Adjust oven rack to 2 inches from broiler and preheat broiler on low. Broil meringue, rotating baking sheet halfway through, until lightly brown and toasted for about 2 minutes.
