Key Lime Bars

A coworker was having a Summer Solstice party so I racked my brain for a summery treat to bring. Everyone loves chocolate, of course, but I wanted to do something different. I’d heard tell of tequila being at this party and I instantly thought of margaritas, which led me to think “Lime!”

I’d found this recipe pretty recently on Mason-Dixon Kitchen, and decided to give it a go. (You should read her entry too if you want straight-forward directions without all my babbling!)

Not knowing how many people would be at the party, I doubled the recipe and baked it in a half sheet, but what I’ve written below is for one 9×13″ pan.

Now, I should warn you that squeezing key lime juice was one of the most unpleasant things I’ve ever had to do. I mean it. It took forever and the limes were too small to put in my citrus juicer so I had to do it by hand. I don’t know that regular limes would have tasted any different, I really don’t know what the difference is aside from appearance, so I’m sure you could sub those if you’d like. It will certainly be easier.

This recipe is done in stages, so I’m laying it out for you how I did it.  Personally, I’d recommend squeezing the limes first because that was such an unpleasant job it’ll be better to get it over with before you do anything else. I’d also suggest smushing/rolling these on the counter top before squeezing them so you can get every last drop from each lime. Actually, before all that, I’d suggest zesting the limes you need before rolling, cutting and squeezing them. You need 2/3 of a cup of lime juice which is a one-pound bag of key limes. Do not worry if your juice isn’t exactly 2/3 of a cup! I didn’t have exactly double with two pounds of lime, and the bars were plenty flavorful anyway.

Another tip – don’t worry about seeds and pulp getting into the juice or it will make you crazy. I squeezed out all the limes into my measuring cup, then ran the juice through a strainer to weed out the seeds. Using a spatula, I squeezed the juice out of the pulp that got trapped in there as well. The pix below are the juice (for a double batch) as well as all the lime rinds! Yes, there were that many. It was a ridiculously sticky and messy process, and I didn’t realize how many cuts I’d had on my hands until I started squeezing. I even ran my hands under water every so often so the citrus didn’t eat away at my skin. (I’m not sure if it actually does or not, but that’s what it sure felt like.)

Here’s the rest of the recipe:



  • 1/2 pound (2 sticks) unsalted butter, at room temperature
  • 1/2 cup granulated sugar
  • 2 cups flour
  • 1/8 teaspoon kosher salt

Lime layer

  • 5 large eggs at room temp
  • 1 2/3 cups granulated sugar
  • 1 tablespoon + 1 teaspoon grated key lime zest (I may have gotten carried away with the zest and done more…)
  • 2/3 cup freshly squeezed key lime juice
  • 2/3 cup flour
  • Powdered sugar, for dusting

Grease a 9×13″ pan and preheat your oven to 350ºF. I used baking spray.

Assuming you’ve already squeezed the limes, then you’ll make the crust, which you’ll bake for a bit before adding the filling. You’ll have a little time to do the other stuff, including the juicing if you need to, because the crust has a short cooling period before adding the filling to bake to completion. To make the crust, cream the butter and sugar together in a mixer. Then, add the flour and salt and mix on low until it’s just combined. I only had enough sugar for the lime layer (don’t ask) so I subbed in brown sugar for the crust. The bars tasted great, but I feel the crust didn’t stay together as well because brown sugar adds a bit of moisture. Just letting you know.

Anyways, now take your dough and press it into your pan, making sure there’s a 1/2″ edge on all sides. This is really important. I don’t think mine was quite 1/2″ in some places, as you can see in the picture below, and when you eventually pour your lime mix in you’ll freak out like I did that it’s just going to run all around the outside edges of your crust instead of staying contained. Bake the crust for 15-20 minutes until lightly browned. Take it out and let it cool on a rack for 10 minutes, but leave your oven on.

While the crust is baking, since you have at least 20 minutes, plus the 10 minutes of cooling, squeeze the lime juice if you need to, and then start on the filling. Rub the zest into the sugar with your fingertips (there’s a ton of zest because, again, I doubled my recipe… there is still probably way more than needed).

Then add the flour, and whisk the dry ingredients together. Then add the lime juice and eggs and mix well. I had a huge problem with this part because everything ended up in clumps. I ended up running it through a strainer and using a spatula to really squeeze the lumps out and into a new bowl. This was also problematic as all the lime zest got caught in the strainer, slowing down the process, but I just dumped it back in the bowl after.

Then, slowly pour the filling on your cooling crust. I say slowly because it’s pretty runny and surprised me how quickly it splashed everywhere. Bake for 20-25 minutes until the filling is set. The lime layer shouldn’t wiggle when moved. (This was a fantastic way to gauge when it was done, jiggling the tray.) Let the bars cool to room temperature then cut and dust with powdered sugar. I put the sugar on first and then cut them in the pan. I’m not sure it really matters. They were tasty and looked just fine. I think you can get 28 (7×4) sizable bars out of a pan, since I got 56 out of the double.

She notes they can be stored at room temp, as long as they’re in a sealed container, for 4 days. You can probably keep them in the fridge for a bit longer. You might just want to re-dust with powdered sugar.

I didn’t get too many comments on these from people aside from that they love lime and these were really good. I do know the hostess of the party had 5 of them for breakfast the next day, so maybe these warrant a 2. They have fruit in them, so they’re kind of healthy… right? 😉



  1. I’m pleased you like them! I think key limes have a flavor kind of in-between regular limes and lemons. I definitely think this could work with regular limes though.

    1. They were so fantastic. I’d be interested to try them with regular limes if only because it would be easier 😉 Lemon bars sound pretty fab too though!

  2. Marianne · · Reply

    Juicing Key Limes is easier if you use a garlic press. This idea came from my sister who lives in the Keys, picks her own limes!! Color me jealous.

    1. That’s a clever idea. I was so excited I had a citrus juicer (holiday present) but the limes were too small! Next time I’ll try the press though, thanks!

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