This no-fuss key lime curd is the perfect way to preserve your homegrown key lime harvest – or the bag of key limes you picked up at the grocery store. The final texture is perfectly smooth with the sweet, tangy, creamy balance we all love about key lime pie filling. Follow the tips and tricks in this recipe for the most foolproof and best-tasting key lime curd possible.
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Every year for my birthday, I always request key lime pie instead of a cake. Nothing beats that sweet-creamy-tangy-crumbly taste in my opinion. No birthday cake, however wonderful, can hold a candle to key lime pie.
Key lime curd is key lime pie in a jar – just add the crust. And my foolproof tips in this Key Lime Curd recipe will ensure that every batch is perfect. There are so many things you can do with homemade citrus curd (stay tuned for ideas), but one of the simplest is to spread this on graham crackers for a quick key lime pie-inspired snack.
When it comes to canning and preserving, always use a well-tested recipe so you can be sure it is safe for long term storage. This recipe is one that I adapted from The National Center for Home Food Preservation’s lemon curd recipe, so I know that it has been thoroughly tested using safe canning practices. Follow the steps precisely for the best, and safest, results. Visit the NCHFP website for lots of great beginner canning information and safe practices.
Growing Key Limes
Any fruit recipe is vastly improved when you use fresh, homegrown, or recently picked fruit. Key limes are actually very easy to grow, even if you’re a gardening novice. They make the perfect container tree for a patio or small garden.
Check out Nature Hills Nursery online to buy a Mexican Key Lime tree, or visit at your local plant nursery. Once it’s settled into a pot with some good quality potting soil, key lime trees need little care other than sun, regular water, and the occasional fertilizing.
I have a ton of resources here on The Fruit Grove for how to grow your own citrus trees in containers. Check out the posts below to learn how to care for your new key lime tree. The taste of homegrown citrus is shockingly superior to any storebought lemon or lime. Try growing your own!
- The Best DIY Citrus Potting Mix Recipe (Plus 5 Brands to Try)
- A Guide to Pruning Potted Lemon and Lime Trees
- Is Your Citrus Tree Overwatered or Underwatered?
- Fertilizing Potted Citrus Trees: Everything You NEED to Know
Recipe Instructions
Step 1:
The first thing to do is mix the sugar and key lime zest. The sugar helps extract oils from the zest, which is where the flavor comes from. The longer the sugar and zest sit together, the more intense the flavor will be. Aim for at least 30 minutes, but you can let it sit as long as overnight.
Step 2:
If you are canning your curd, prepare the lids, jars, and water bath canner. Clean the jars with soap and hot water. Heat the canning water to 180°F and lower the heat to maintain that temperature. This is one of those crucial canning tips – if the water is too hot when you add the filled jars, it will affect the processing time and the jars may not seal correctly.
Also prepare your double boiler set up. I used a heavy-bottomed saucepan with a glass mixing bowl on top. Fill the saucepan with about an inch of water and heat until it is just barely simmering – as long as there is steam, it’s hot enough. You don’t want a vigorous boil. The bowl should fit inside the pan with enough space so the bottom of the bowl won’t touch the simmering water.
Step 3:
In the heat-proof bowl (the one used for the top of the double boiler), off the heat, whisk together the eggs and sugar/zest mixture. Add in the lemon juice. Then add the butter pieces.
Put the bowl back on top of the simmering water and stir with a rubber spatula until the butter melts. Insert a kitchen thermometer or candy thermometer, and continue cooking (and stirring) the curd until it reaches 170°F. It should be thickened, but it will continue to get thicker as it cools.
Step 4:
Remove the bowl with the curd from the double boiler. Continue stirring for about 5 minutes to allow the curd to thicken up. Strain the curd through a mesh strainer to get out any lumps.
Fill the jars with the curd, leaving ½ inch of headspace below the rim of the jar. This is another key canning tip. The headspace will affect how well the jar seals as they process. Clean the rim of each jar with a damp paper towel, then top with a prepared lid. Tighten the ring so it’s on securely but not overly tight.
Step 5:
Place the filled jars in the preheated canning water, then turn up the heat and bring to a full rolling boil. This may take 10-20 minutes. Once the water is boiling, process the jars for 15 minutes if you live at less than 1000 feet above sea level. For higher elevations, process 20 minutes (1000-6000 feet) or 25 minutes (higher than 6000 feet). At the end of the processing time, turn off the heat and let the jars sit in the water for another 5 minutes to settle. Then carefully remove the jars to a towel-lined counter or table.
Let the jars cool at room temperature for 12-24 hours. If any cooled jars still aren’t sealed, put those in the fridge and eat within the next few weeks. Sealed jars can be stored in a cool, dark place for up to 3 to 4 months. Key lime pie at the ready!
Foolproof Key Lime Curd (+ Canning Instructions)
Equipment
- Microplane or zester
- whisk
- Heavy-bottomed saucepan with a heatproof bowl that fits inside (or double boiler)
- Kitchen thermometer
- Fine-mesh strainer
- Silicone spatula
- Large pot or boiling water canner
- Half-pint glass jars, lids, and rings for canning
- Jar lifter
Ingredients
- 1 cup bottled or fresh key lime juice *see notes
- 1/3 cup fresh key lime zest
- 2 ½ cups granulated sugar
- ¾ cup unsalted butter chilled and cut into small cubes
- 7 egg yolks
- 4 whole eggs
Instructions
Prepare Canning Equipment
- Fill boiling water canner or large pot with enough water to cover the full jars by at least an inch. Heat the water until it reaches 180℉ and lower the heat to maintain the temperature while you make the curd (*see notes).
- Wash the canning jars with warm water and soap and rinse well. Keep the jars warm in the hot water until you are ready to fill them with the curd. Heat the lids as needed to soften the seals.
Make the Curd
- While the water is heating, mix the sugar and key lime zest in a small bowl and set aside for at least 30 minutes. Measure out the lime juice and cut the butter into small pieces (if you haven’t already).
- Fill a saucepan with about an inch of water. Bring the water to a boil, then lower the heat to maintain a slow simmer. Place the heatproof bowl on top of the simmering water to check that the water does not touch the bottom of the bowl. The water should not bubble too vigorously (it should be barely simmering).
- Off the heat, in the heatproof bowl, whisk the egg yolks and whole eggs until thoroughly combined. Slowly add the sugar/zest mixture and whisk until everything is smooth. Add the lemon juice and butter pieces and stir to combine.
- Place the bowl on top of the pan of simmering water. Stir continuously (gently) with a rubber spatula until the butter has melted and is incorporated into the mixture. Continue cooking and stirring until the curd has thickened somewhat and has reached 170℉. The curd will continue to thicken as it cools.
- Remove the bowl from the double boiler and move to a towel on a table or counter. Continue stirring for about 5 minutes until the curd thickens more. Strain the curd through the fine-mesh strainer to make sure there are no lumps or eggy bits.
Canning Instructions
- Fill each clean, hot jar with the still-hot curd, and leave 1/2 inch of headspace between the curd and the top of the jar. Wipe the rim of the jar clean with a damp paper towel, then place prepared lid on top. Twist on a ring until it is closed but not too tight.
- Carefully lower the filled, lidded jars into the 180℉ water in the pot. Increase the heat to high and bring to a boil (this may take 10-20 minutes). Process for 15 minutes if you live at lower than 1000 feet elevation (20 minutes for 1000-6000 ft, 25 minutes for 6000 ft and above). After processing time, turn off the heat and leave the jars in the hot water for about 5 minutes to allow the contents to settle. Lift the jars out and place on a towel on a table or counter. Allow the curd to cool on the counter for the next 24 hours. If there are any unsealed jars, store them in the refrigerator and eat within the next 2 weeks.
- Store sealed jars in a cool, dry place like a pantry. Use within 3 to 4 months. If you notice any color changes or separation, discard the curd.
TIPS
- I adapted this recipe from one developed by the National Center for Home Food Preservation using canned lemon or lime juice, which has a consistent acidity level. The acidity of fresh juice can vary, so for best (and safest) results, use bottled key lime juice. However, because I am using fresh key limes, I used about half fresh and half bottled juice, which worked beautifully and tasted amazing. Even less acidic limes should have a high enough acidity to make the canning safe, but if you are concerned, use bottled key lime juice.
- Regular limes and lime juice can be substituted for the key limes for a regular lime curd.
- Don’t heat the water higher than 180* before adding the jars. The temperature of the water affects the processing time, so to be sure the jars process safely and correctly, keep the water temperature at 180 until the jars are added. Increase the heat until the water is boiling, then begin the processing time.
- You can also freeze the key lime curd if you don’t want to can it. After straining, pour the curd in freezer-safe airtight containers and allow it to come to room temperature. Then freeze it for up to a year. Thaw frozen curd in the refrigerator for 24 hours before you want to use it and use the thawed curd within 2 to 4 weeks.
