By Claire Saffitz
- Total Time
- 1½ hours, plus 1 hour’s cooling
- Rating
- 4(451)
- Notes
- Read community notes
These rich yet refreshing lime bars are for citrus lovers who appreciate puckering acidity in their desserts. The curd filling contains a bit of cornstarch, so it sets firmly in the oven, allowing you to slice, stack and store the bars easily. A little fresh mint inside the shortbread crust — which is made entirely by hand — adds an herbal complement to the lime.
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Ingredients
Yield:16 bars
- Unsalted butter, for greasing the pan
- 2tablespoons finely grated lime zest (from about 3 limes)
- ¼cup/50 grams granulated sugar
- 1cup/130 grams all-purpose flour
- 2packed tablespoons finely chopped fresh mint
- ¼teaspoon baking powder
- Pinch of kosher salt (Diamond Crystal)
- ½cup/113 grams cold unsalted butter, cut into ½-inch pieces
- ¾cup/170 grams fresh lime juice (from about 7 limes)
- ¼cup/57 grams fresh lemon juice (from about 1 large lemon)
- 1teaspoon cornstarch
- Pinch of kosher salt (Diamond Crystal)
- 1cup/200 grams granulated sugar
- 5large egg yolks
- 1large egg
- 6tablespoons/85 grams cold unsalted butter, cut into tablespoons
- Confectioners’ sugar and finely grated lime zest, for serving
For the Shortbread Crust
For the Lime Curd
Ingredient Substitution Guide
Nutritional analysis per serving (16 servings)
214 calories; 13 grams fat; 7 grams saturated fat; 0 grams trans fat; 4 grams monounsaturated fat; 1 gram polyunsaturated fat; 24 grams carbohydrates; 0 grams dietary fiber; 17 grams sugars; 2 grams protein; 30 milligrams sodium
Note: The information shown is Edamam’s estimate based on available ingredients and preparation. It should not be considered a substitute for a professional nutritionist’s advice.
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Preparation
Step
1
Arrange an oven rack in the center position and heat the oven to 350 degrees. Line an 8-inch square pan, preferably metal, with 2 sheets of aluminum foil, crossing one over the other and pressing the foil into the corners and up the sides. Butter the bottom and sides of the foil, and set the pan aside.
Step
2
Make the shortbread crust: In a medium bowl, use your fingertips to massage the lime zest into the sugar until the fragrant oils are released and the mixture looks like wet sand. Add the flour, chopped mint, baking powder and salt, and toss to combine. Add the ½-inch pieces of chilled butter and toss to coat in the flour mixture. Use your fingertips to smash the butter into the flour mixture, working until no large pieces remain and you have lots of moist crumbs that hold together easily when squeezed.
Step
3
Bake the crust: Scatter the shortbread dough evenly across the bottom of the prepared pan. Use your hands to flatten the crumbs into an even layer, working it into the corners and against the sides. Bake the shortbread until lightly golden across the surface, about 30 minutes. Remove the pan from the oven. (Leave the oven on and reduce the temperature to 300 degrees.) Let the crust cool while you make the filling.
Step
4
Make the lime curd filling: In a small saucepan, combine the lime juice, lemon juice, cornstarch, salt and ½ cup/100 grams of the granulated sugar, and cook over medium heat, whisking occasionally, to dissolve the sugar. When the mixture comes to a boil, whisk constantly until it thickens slightly from the cornstarch, about 1 minute, then remove the saucepan from the heat.
Step
5
In a medium bowl, vigorously whisk the egg yolks, whole egg and remaining ½ cup/100 grams sugar until the mixture is smooth, thick and has paled in color a couple of shades, about 1 minute. Whisking constantly, slowly drizzle the hot citrus mixture into the eggs a tablespoon at a time to slowly raise the temperature, until you’ve added about half the citrus mixture to the eggs.
Step
6
Whisk the egg mixture back into the saucepan, then set back over medium-low heat and cook, whisking constantly, until the curd turns opaque, is thick enough to coat the back of a spoon and barely hold the marks of the whisk (it will register 170 degrees on an instant-read thermometer), about 5 minutes. Remove the curd from the heat and whisk in the butter a piece at a time, waiting until each piece melts before adding the next, until the mixture is smooth.
Step
7
Bake the bars: Pour the hot curd over the crust and shake the pan gently so it settles in an even layer. Bake the bars until the sides have puffed and the center is set but still a bit wobbly when you shake the pan, 30 to 35 minutes. Remove from the oven and let the bars cool completely in the pan
Step
8
Chill before serving: Transfer the cooled pan to the refrigerator and chill until the bottom of the pan is cold to the touch, about 1 hour. This will harden the butter in both the curd and crust, making it easier to remove the bars from the pan and slice.
Step
9
Use the edges of the foil to lift the bars out of the pan, then peel down the sides of the foil and slide a metal spatula underneath to loosen the crust from the foil. Slide the bars off the foil onto a cutting board and slice into 16 squares. Dust with confectioners’ sugar and top with more lime zest before serving. They are best eaten on the first or second day, but will keep for up to 5 days stored in an airtight container in the refrigerator.
Tip
- se the edges of the foil to lift the bars out of the pan, then peel down the sides of the foil and slide a metal spatula underneath to loosen the crust from the foil. Slide the bars off the foil onto a cutting board and slice into 16 squares. Dust with confectioners’ sugar and top with more lime zest before serving. They are best eaten on the first or second day, but will keep for up to 5 days stored in an airtight container in the refrigerator.
Ratings
4
out of 5
451
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Private Notes
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Cooking Notes
Ellen Lockhart
I use passion fruit from my garden on Saba, Dutch Caribbean, for the curd. It is a success.
sophia
delicious and extra sour break from your more traditional christmas flavors! after reading the notes, i was careful to make sure my curd mixture was thickening at each point and was not disappointed in the final texture. I let the mixture bubble for more than 1 minute during the first boil for the juice/sugar/cornstarch mixture and the curd had a very thick consistency even before going into the oven. the flavor was very limey and tart, with minor hints of mint
jessie
I’ve been cooking NYT recipes for years, and never been disappointed until making this one. I followed the recipe to a “T”, but they never properly set (even though I added cooking time, and eventually upped the temp) - it was liquid the whole time in the oven! Even after fully chilling, they have a sticky jelly-like texture rather than creamy and luscious as hoped. The oil from the butter split and was pooling on top…the mint and lime flavors didn’t go together…and more. Do not recommend.
mechteach
The flavors were very tart, which was perfect, but there wasn't enough mint. I was hoping for the flavor of the sort of limeade/lemonade crammed with fresh mint leaves you can get at some beaches. Also, sophia is spot on with allowing more time for thickening at the two points - that seems crucial. I don't think the balance of the shortcrust and curd is perfect - too much crust for me. Next time, I'll cut that to 3/4. Made meringue cookies with the extra egg whites - nice sweet balance.
Unique and delicious
These turned out very sour with just a hint of mint. I love them! But they are certainly not a traditional Christmas cookie. Agreed with other commenters that the curd needs to be thickened longer than directed. As I told my 10 year old budding baker daughter who made these with me, it’s all about the consistency, the time they write is just an estimate. Thankfully I’ve made curd previously (a long time ago) so I knew to ignore the time and look for it to actually thicken at both points.
Ann
Key Lime Pie BY DEFINITION uses sweetened condensed milk. One (of many) sources says: "No fresh milk, no refrigeration, and no ice was available in the Keys until the arrival of tank trucks with the opening of the Overseas Highway in 1930. Because of this lack of milk, local cooks had to rely on canned sweetened condensed milk... Key lime may be the star ingredient of the key lime pie, but it is the sweetened condensed milk that makes it so smooth and delicious."
Madison Cook
THIS is the curd method my mother used to make TRUE lemon and/or key lime meringue pie in the era before popularization of today’s faux short-cut and disappointing sweetened condensed milk version that proliferates every contemporary recipe source (sorry, including the current NYT). Can’t wait to try these bars. Thank you, Claire!
ashley
the lime bars were super delish but got stuck in the pan! make sure there is no way the curd can seep through the corners of the foil and don’t be shy about buttering the foil—I wasn’t able to pull the bars out of the pan and lost a lot of them while trying to get them out.it also developed an eggy film on the top of the curd after baking but I was able to peel it off really easily.
Katie Kaminski
Can you use gluten free flour?
c.mere
So sour and very delicious. I failed to read the comments before and didn’t allow as much extra time for thickening as I should have. They set but were softer than should have been even with a few minutes longer at each step. Would make again for a sour loving someone.
Ash E
I've made this recipe as written a few times and it is A . A tropical variation I tried with great success:For the crust: omit zest and mint. add 1/2 cup sweetened dried coconut flakes and reduce sugar by half For the curd: swap pineapple juice (I used Dole brand) for the lime juiceThe shortbread base was a bit crunchier but I enjoyed that. Will be making both versions again!!!
Nicole
Just tried this variation per your recommendation - fantastic!!!!! My boyfriend said it was the best desssert I've ever made.
Jack F
Agree with pretty much every other baker here - the curd doesn’t set even if you follow directions verbatim. In what alternate universe does a cup of liquid (lime + lemon juice) thicken with a mere teaspoon of cornstarch?Unlike any other curd recipe I’ve seen. Now I’m reluctant to try any other of the author’s recipes…
Jonathan
This recipe didn't work. I followed it exactly as written, including temping the curd as I heated it. The result was soupy liquid curd after 30 minutes in the oven. By the time the curd had set, after almost an hour in the oven, the crust was burnt.
Pat
This is a complicated recipe and although the flavors and textures are good, the final product was not a great success. I cooked the final step for 35 min because of the comments about a runny curd. Curd texture was fine, but the top had a brown crust, and the shortbread was overdone. It is a very rich, tart dessert. If I try again, I will cook for less time.
1ndig0
One of the more technical key lime bar recipes I've tried. For the shortbread crust though I added the zest+sugar to room temp butter and fluffed it together, then added the rest into that. Otherwise followed the instructions, and everything came out right. This is at least 1/2 cup key lime juice more than what I'm used to, and it was way too tart from the typical key lime bar. Also uses a lot more eggs resulting in a darker bar. Next time I'll try adding vanilla and mint to key lime curd.
Linda B
Fail. Followed recipe and curd never set; butter pooled and the lemon curd remained jiggly. Huge disappointment and a waste of six eggs and butter. I had much better results with Tanis’s cranberry curd tart.
Bas M.
it sounds like your curd was not set enough before you added in the butter. you need to cook out the eggs during the middle step while continuously whisking like a lady gone mad. it takes quite some time and I don’t think that was evident from the video. you really want it to be thick and coating the spoon like in the video, before you add butter. also add the butter SLOWLY and whisk from top to bottom of the pot making sure all of the butter is incorporated.
Linda B
Fail. Same results as above. Curd never gelled and separated in the oven, creating pools of butter. Huge waste of six eggs. This recipe is in her book and I baked before I realized the recipe and comments were online. Hugely disappointing.
Julie
Like Jessie, I followed the recipe very carefully but the curd broke and was a melted butter mess. So disappointed!
Gina
I did not follow her curd recipe. I use one that is way easier and has fewer ingredients. I would go with a basic curd recipe, ie, one that does not require corn starch nor egg whites. I love the "limeyness" of this recipe!
Denise Evans
These are quite tart and absolutely fantastically delicious. Made no changes. A keeper and repeater!
Margarita
Made these in a pan 9x9 square springform pan. Brilliant. Baked a little too long but and therefore are super crunchy. Bake slightly less and will be perfect next time. Followed directions exactly.
well its sort of good
The final result was SORT OF tasty. The lime flavor was wonderful but was overshadowed by an eggy tang… Since baking this recipe I’ve read that the egg white is what gives that sulfurous tang. I think I will try this again but use the egg yolk/cornstarch ratios from the NYT vanilla creme brûlée recipe.Also the mint in the short bread just made the crust taste like a pot cookie. No mint flavor - just earthy.
Marisol
I used a tablespoon of cornstarch rather than a teaspoon and then all the thickening directions worked and the consistency at the end was correct.
Eva
I had to cook mine in one of those foil single-use pans you can find in grocery stores because I was traveling, but it turned out great! Just buttered the pan directly and did not use extra tinfoil. Put the whole thing in the fridge to chill, and cut them after an hour. The nice thing about those pans is you can put right through the bottom of the pan and just remove that part, leaving a nice square lime bar! I also had to whisk and cook the curd for closer to 10 mins to get it to thicken.
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