Keto Key Lime Pie
Published April 3, 2022 • Updated February 2, 2026
A silky flavorful lime filling on a flaky low-carb pie crust
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This key lime pie will please everyone - even your non-keto friends and family. We start with a flaky, buttery pie crust and fill it with a creamy, velvety lime filling. We don't have to cheat and use cream cheese for the filling. Instead, we make our own sweetened condensed milk - just like the traditional recipe uses!
I always like to have a few desserts that I can bring for the holidays (like Easter or Mother’s Day) or to a summer potluck. This keto key lime pie is one of those that I know will be a crowd pleaser no matter what eating lifestyle they follow. Just like my peanut butter pie or my chocolate cream pie.
For this pie recipe, we nailed the combination of tart and sweet that makes it absolutely irresistible. Fresh limes are used in the filling. Even though the title says key lime, you don’t have to use key limes. Regular limes work great. To balance the tartness, we make our own sugar free sweetened condensed milk – which is really easy to make and can be made ahead of time.
Other low-carb key lime pie recipes use cream cheese to thicken their lime filling, but that strays from the original flavor. Most classic recipes use sweetened condensed milk to thicken and sweeten the pie. Unfortunately, store bought sweetened condensed milk is loaded with sugar, but it’s really easy to make your own.
Key lime pie is one of those desserts where you’ll want a second slice. It’s perfect for a hot summer day or a Spring holiday party.
How to make key lime pie
- Make sugar free sweetened condensed milk. Combine butter, powdered sweetener and heavy cream in a saucepan and let simmer for 30 minutes until thickened. Refrigerate for at least 2 hours. This can be made ahead of time. It will stay fresh in the refrigerator for up to 2-3 weeks or you can freeze it!
- Prepare key lime filling. Combine egg yolks with lime zest. Stir in the sweetened condensed milk you made earlier. Then slowly stir in freshly squeezed lime juice. Set aside for 30 minutes to thicken.
- Blind bake the pie crust. Prepare a batch of flaky pie crust. You can also make a graham cracker crust if you prefer that flavor. Bake crust for 8 minutes.
- Assemble pie. Pour key lime filling into cooled pie crust and bake.
- Refrigerate pie. The lime pie will continue to set as it cools in the refrigerator for 2 hours.
- Top with whipped cream. Make your own sugar free whipped cream by combining heavy whipping cream and powdered sugar free sweetener.
Key ingredients
- Sugar free sweetened condensed milk – In this recipe, we start by making our own sweetened condensed milk. It’s easier than you think and only requires 3 ingredients – butter, powdered sweetener and heavy cream. This can be prepped ahead of time, so if you’re making this pie for a special occasion and want to save time, make a batch a few days before.
- Egg yolks – Egg yolks are used to help thicken the pie. When combined with the acid from the key lime juice, the filling will solidify after baking and cooling.
- Lime zest & lime juice – To maximize the tart lime flavoring, we add fresh lime zest. This allows for that punch of lime flavor without all the extra carbs from the key lime juice.
- Low-carb pie crust – For this pie, we’re using my buttery, flaky pie crust, but another option is this basic crust. It tastes similar to a graham cracker crust.
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Keto Sweetened Condensed Milk Ingredients
3 tablespoons unsalted butter -
1/2 cup powdered sugar-free sweetener
-
16 oz (2 cups) heavy whipping cream
Key Lime Pie Filling Ingredients
-
4 teaspoons lime zest
-
4 egg yolks
-
1/2 cup lime juice (from 4 limes or 20 key limes)
Keto Pie Crust Ingredients
-
1 cup almond flour
-
3 tablespoons coconut flour
-
1 teaspoon xanthan gum
-
1/2 teaspoon salt
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1/2 cup unsalted butter, chilled and cubed
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1 ounce cream cheese, softened
-
1 egg
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1 1/2 teaspoons rice vinegar or apple cider vinegar
Keto Whipped Cream Ingredients
-
1/2 cup heavy whipping cream
-
2 tablespoons powdered sugar-free sweetener
Step by Step Instructions
Step by Step Instructions
Make sugar free sweetened condensed milk
To a medium saucepan, add butter, powdered sugar free sweetener and heavy cream. Bring to boil over medium heat. Reduce heat and let simmer for 30 minutes to thicken. Remove from heat and pour into a mason jar or similar container. Let cool at room temperature for about 30 minutes before transferring in the refrigerator for 2 hours.
- Butter
- Powdered sugar free sweetener
- Heavy whipping cream
Prepare key lime filling - whisk yolks with zest
In a medium glass bowl, whisk together lime zest with egg yolks. Whisk for about 2 minutes. Add sweetened condensed milk prepared earlier and stir until smooth.
- Lime zest
- Egg yolks
- Keto sweetened condensed milk (prepared from step 1)
Prepare key lime filling - add lime juice
Stirring by hand with a whisk, very slowly stir lime juice into the filling mixture. Set aside for 30 minutes to thicken slightly. Move onto the pie crust.
- Fresh lime juice
Prepare the pie crust
To a food processer, pulse together almond flour, coconut flour, xanthan gum and salt. Add in cubed butter, cream cheese, egg and vinegar. Pulse until just combined.
- Almond flour
- Coconut flour
- Xanthan gum
- Salt
- Butter (cubed & chilled)
- Cream cheese (softened)
- Egg
- Vinegar
Roll out pie crust and blind bake
Roll out pie crust in between two sheets of parchment paper until the crust is a large circle about 1/8 – 1/4 inch thick. Refrigerate dough for 15 minutes. Remove the top layer of parchment paper and place pie plate upside down over the dough. Slide a hand under the bottom layer of parchment paper, place other hand on top of pie plate and flip over. Remove the parchment paper and press the pie dough into the pie pan. Bake at 350 degrees for 8 minutes. Lower heat to 325 degrees and let cool for about 20 minutes.
Assemble the pie
Pour lime filling into the cooled pie crust. Bake at 325 degrees for 15-20 minutes, until edges are slightly set but the center still jiggles like jello. Refrigerate for 2-3 hours or until set.
Nutrition disclaimer
The nutrition information provided is an estimate and is for informational purposes only. I am a Doctor of Pharmacy (Pharm.D.); however, this content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always consult your physician or other qualified health provider before making any lifestyle changes or beginning a new nutrition program.
Can you make this with the one on one key lime flavor instead of real limes?
I'm not sure how well that will work. It might work just fine, but the acid from the lime juice works with the egg yolks to solidify and thicken the pie when baked.
578 calories a slice? Well, it better be good! (And I am sure it is.)
The prep output looked great . Then when I baked the pie crust it melted, and never cooked. I used oat flour instead of almond , And it went down hill from there :(.
I also couldn’t get the pie texture right , too liquidity.
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