This keto key lime pie is sweet and creamy, with a tender crust and a rich lime custard filling. It’s just as delicious as the real deal, and will have your tastebuds dancing for joy.
Whip up a batch of my sugar free condensed milk and get baking today!
Keto pie lovers, rejoice! And add this sweet and tangy keto key lime pie to your baking list right away. It’s a classic and now it’s completely sugar free and grain free.
One might wonder what took me so long to create a low carb key lime pie recipe. After all, I have several recipes that use those tangy flavors, like keto key lime bars and key lime pound cake.
Let’s just say that I don’t like to release recipes into the world until they meet my standards. My late father adored key lime pie, and it was important to me to perfect a low carb version before I posted it.
Classic style recipe
This sugar free pie is made in the classic style, with a custard filling made with egg yolks, sweetened condensed milk, and lime juice. I very much wanted to stay true to the original.
This was tricky to get right, since sugar is one of the ingredients that helps traditional key lime pie set properly.
That’s why so many keto recipes rely on cream cheese to help set the filling. As tasty as that is, it’s more cheesecake than custard.
To get true keto key lime pie with my homemade condensed milk, I found that I needed to use another egg yolk to help it set.
Keto Graham Cracker Crust
Traditional key lime pie features a graham cracker crust, and many readers as me if they can use my keto graham crackers for this. And you certainly can do that, but it’s a lot of wasted effort, if you ask me.
Think about it: first you have to make the graham crackers, then crumble them in a food processor, measure them out, mix them into a crust, and bake them again.
Whereas you can simply take all the ingredients that make up the graham crackers, whisk them together, press them into a pan, and bake once. It’s so much easier and tastes exactly the same.
I shared some of this keto key lime pie with a neighbour and received a text later that said the pie was great and the crust was out of this world!
Tips for keto key lime pie
Once you have the sugar free condensed milk and crust ready to go, this pie is a snap to make. Here are my best tips for getting it right:
- Make the condensed milk. It needs to cool completely so make this in advance of the crust. You can even make it the day before and refrigerate it overnight. It will thicken a lot in the fridge but you can simply let it come to room temperature and it will loosen up again.
- Prep the crust. This is a modified version of my easy keto pie crust, with Swerve Brown and a touch of cinnamon to make it taste more like a graham cracker crust.
- Par-bake the crust. About 12 minutes in the oven will help the crust set nicely before you add the key lime filling.
- Beat the egg yolks. I gathered some great tips from this recipe on King Arthur Baking. Beating the yolks until they thicken helps set the pie and make the filling super creamy.
- Beat in the condensed milk. You want to beat this until the mixture increases in volume, which again makes the filling lusciously smooth and creamy.
- Bake the pie. I recommend covering it in foil for the first 30 minutes to keep the crust from over-browning.
- Chill the pie. Patience, friend! A good keto key lime pie needs to chill and set for at least 3 hours.
Frequently Asked Questions
Absolutely. Key limes are tiny and hard to squeeze for juice, so regular Persian limes will work just as well.
You can use different sweeteners in the crust and the filling but please bear in mind that only erythritol-based sweeteners will produce a crisp crust. And using some BochaSweet or allulose in the condensed milk is best to avoid recrystallization.
Read more about different sweeteners work in my Guide to Keto Sweeteners.
Yes, you can make this recipe without dairy. For the condensed milk, use coconut cream to replace the heavy whipping cream. And use coconut oil or other non-dairy butter in the crust.
Storage information
Because it’s custard based, the keto key lime pie should be refrigerated at all times. It will last up to 5 days in the fridge.
This is not a great recipe for freezing, as the filling may change consistency.
More delicious keto pie recipes
- Keto Peanut Butter Pie
- Sugar Free Pecan Pie
- Keto Pumpkin Cream Pie
- Lemon Sour Cream Pie
- Keto Coconut Cream Pie
- Sky High Chocolate Mousse Pie
Keto Key Lime Pie Recipe
Ingredients
Crust
- 1 1/4 cup almond flour
- 1/4 cup Swerve Brown
- 1/4 tsp cinnamon
- 1/4 tsp salt
- 3 1/2 tbsp butter melted
Filling
- 4 large egg yolks
- 1 tbsp key lime zest
- 1 recipe recipe Sugar Free Condensed Milk (cooled)
- 1/3 cup fresh key lime juice
- 1/4 cup powdered Swerve Sweetener
Instructions
Crust
- Preheat the oven to 325F.
- In a large bowl, whisk together the almond flour, brown sugar substitute, cinnamon, and salt, breaking up the clumps. Stir in the butter until well combined.
- Press firmly into the bottom and up the sides of a glass or ceramic pie plate. Crimp the edges decoratively.
- Bake 12 minutes, until just beginning to brown around the edges. Remove and let cool completely.
Filling
- In a large bowl, beat the egg yolks with the lime zest for 3 to 4 minutes, until thickened and paler in color.
- Add the condensed milk and beat for another 4 minutes, until the mixture has increased in volume. Beat in the lime juice and powdered sweetener.
- Pour the mixture into the cooled pie crust. Cover the pie with foil (shiny side up) and return the pie to the oven at 325F.
- Bake 30 minutes, then remove the foil and bake uncovered for another 10 minutes or so. The filling should be set around the edges but still a little jiggly in the center.
- Remove and let cool completely, then refrigerate 2 to 3 hours to set.
Mark says
Hi Carolyn, I can’t wait to make this, it sounds incredible! I’ve been craving key lime pie for years since I’ve changed my diet! I just want to confirm, you use the whole amount of the condensed milk? The recipe for the pie lists 1 recipe of the condensed milk as an ingredient , so I just want to confirm this as the condensed milk recipe says it’s 8 servings.
Also, can I make this pie crust a day in advance and par bake it the next day when I make the pie?
Thank you!
Mark
Carolyn says
Yep, full amount of the condensed milk. It ends up being about a cup… maybe a little more.
Carolyn says
Oh yes and the crust should be fine prepped in advance.
Mark says
Thank you so much!
Terri says
Would it be possible to make the filling in ramekins and not make a larger pie with a crust??
Carolyn says
No idea, I didn’t make the pie that way.
2pots2cook says
Oh boy ! Already dancing !!!! 🙂 Printing to make !
Carol Gersten says
Hi Carolyn,
I’m the cook who asked you about the amount of xantham powder to use in order to make mass quantities of your condensed milk to convert my classic key lime pie recipe. You asked me to wait and now I see why. This looks awesome and I can’t wait to make it (maybe this weekend)! My question for today is: What size pie plate do you use for this recipe. I have a 10 inch, deep dish pie plate and I am afraid that after making the crust and pouring in the filling only half of the pie plate will be filled. I think this because my regular recipe calls for two 14 ox cans of sweetened condensed milk. I will get a smaller or more shallow pie plate if I need to. I just need to know before I start on this wonderful project. Thank you!
Carolyn says
So my fear with a deeper pie is that it will take longer to set and you may burn the crust trying. But if you want to experiment, I recommend a filling that’s 1.5 times the amount in mine, not 2x. Since your pan is not the standard 9 inches, then that would be about right. I have one deep dish pie plate and when I used it, I have the crust only come up about 3/4 of the way, to match the filling.
Carol G says
Thanks Carolyn! I get what you’re saying. I may buy a 9 inch pie plate for this recipe.as I’m wondering if the cream pie to crust ratio may be overboard with my 10 inch deep dish plate. By the way, I made your key lime bars and my husband and friends can’t stop raving! They think I’m a baking wizard but it’s clear you’re the “little man behind the curtain”! Thank you again!
Carolyn says
Great to hear!
Jennifer Davis says
My hubby is a fan of key lime pie. So I think I must make him one….. approximately how many of those key limes will I need? I realize that the individual juiciness of the limes will vary….but…. I ve never worked with key limes before…. thanks for your wonderful recipe….love from Calgary!
Carolyn says
They are a pain, I will admit. But they usually come in a bag together of about a pound and you’d need about half of them.
Simone says
Condensed milk is in the fridge to cool down- now I just have to hunt down Key Limes. I have a question though: What size is your pie form? Thank you
Lynda Savage says
You are the Queen of Keto baking and cooking! I love your recipes and you explain everything so well/ I like your tats too.
Roberta says
Apologize my ignorance, but I can’t understand what does it mean “Cover the pie with foil (shiny side up)”… I literaly understand of course, but I can’t get the point about the shiny side of foil: I’ve always seen foil looking the same on both sides… Is there a particular kjind of foil that has two layers/sides? Thank you if you’ll explain this point to those who’re not used to this material and are discovering it just now. And in the case it wasn’t avaible, wouldn’t regular aluminium foil work as well?
Carolyn says
There is most certainly a shiny side and a duller side. Since the shiny side reflects heat, you want it up so that it reflects the heat AWAY from the pie. And this is all aluminum foil. Take a closer look, you will see the difference.
Tracy Andries says
Hi Carolyn. I didn’t see your answer before I answered. 😆
Roberta says
Thank you for your accurate answer, Carolyn and Tracey! I have promptly observed with scientific eye the aluminium foil I have in my cabinet, but believe me or not both sides looks the same (to me but also to my mother who I called to have another opinion about that); I have looked also to another one I have bought last week, still new and of nother brand (not a famous one, found at the supermarket ), but it’s the same. Then I remember I had ordered a couple of other aluminium foil rolls from a website where usually buy other things for bakking and here it was a kind of what you are explaining me about 🙂 From now on I’ll try to buy just this kind, in the case in my Country it was not so common and prevalent as in the US.
So happy I have noticed the difference, and grateful to you for having helped me to get the best from this and improve… I already knew, thanks to your explanation and teaching bout the reaction of aluminium reflecting heat and its conductivity rather than other material in baking, but as I saw here there’s always something more to learn 🙂
Carolyn says
I certainly believe you. I didn’t realize you weren’t in North America. 🙂
Tracy Andries says
Hi Roberta. Just thought I’d answer your question on foil. There is a shiny side and a dull side to foil.
You should be able to see it. One side draws in the heat and the other directs the heat away. Hope that helps.