Keto Key Lime Pie
Published April 3, 2022 • Updated March 11, 2026
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I make this keto key lime pie with homemade sweetened condensed milk instead of cream cheese, and the difference is night and day. Silky, tart filling on a flaky, buttery crust that holds up perfectly.
I always have a few desserts ready for holidays, summer potlucks, and those nights when someone says “what’s for dessert” and I want to hand them something that ends the conversation. This is that dessert. Just like my peanut butter pie or my chocolate cream pie, it disappears fast and nobody asks if it’s keto.
Most low carb key lime pie recipes use cream cheese to thicken the filling. I get why (it’s easier), but it doesn’t taste right. You end up with something closer to a cheesecake than the real thing. I chose to make my own sugar free sweetened condensed milk instead, and that one decision changes everything. The filling comes out smooth, tart, and silky, exactly like the version I grew up eating.
The condensed milk takes about 30 minutes to simmer, plus a couple hours to chill, but I make it a day or two ahead so the actual pie assembly is fast. Three ingredients: butter, powdered sweetener, and heavy cream. If you use allulose instead of an erythritol-based sweetener, it won’t crystallize, which I learned after testing both side by side. Allulose stays smooth. Erythritol works but can get a slight crunch if it doesn’t fully dissolve.
For the crust, I use my flaky keto pie crust. It’s almond flour-based with a little coconut flour and xanthan gum, and it holds up under a wet filling without getting soggy. I blind bake it at 350 for 8 minutes, then drop the temp to 325 before the filling goes in.
The filling itself is three steps: whisk yolks with lime zest for a couple minutes (this pulls out more color and flavor), fold in the condensed milk, then slowly drizzle in the lime juice. And I mean slowly. If you pour the juice in too fast, it curdles. I drizzle it in while whisking and then let the whole thing sit for 30 minutes before it goes into the crust. By that point it’s already starting to thicken from the acid reacting with the egg yolks.
One thing I changed from the original version: I now tell people to refrigerate for at least 4 hours, not 2. At 2 hours the center is still soft and the slices don’t hold shape. Reader Mia confirmed the same thing. Four hours and it slices clean. Overnight is even better.
I bring this to every summer gathering and it works alongside my coconut cream pie, strawberry pie, or banana cream pie when I want a full dessert spread. The tart-sweet balance is the kind of thing that makes people go quiet mid-bite, which is always a good sign.
How to make this pie
I prep this in three stages, and the order matters. The condensed milk goes first because it needs at least 2 hours in the fridge (overnight is better). Then the crust, then the filling last.
Key ingredients
- Sugar free sweetened condensed milk – I make my own with just butter, powdered sweetener, and heavy cream. Thirty minutes of simmering, then it chills. I prep it days ahead because it keeps for 2-3 weeks in the fridge. This is what separates the filling from those cream cheese versions.
- Egg yolks – The acid from the lime juice reacts with the egg yolks to thicken and set the filling as it bakes and cools. Chemistry, not gelatin.
- Lime zest and lime juice – I add the zest first and whisk it with the yolks for 2 minutes to pull out extra flavor and color without adding carbs from extra juice. Then the juice goes in slowly, or it curdles.
- Low carb pie crust – I use my flaky pie crust for this. Almond flour, coconut flour, xanthan gum, cold butter. It blind bakes cleanly and holds up under a wet filling.
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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
-
1/2 cup unsalted butter, chilled and cubed
-
1 ounce cream cheese, softened
-
1 egg
-
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.
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Get My Macros + Recipes →Frequently Asked Questions
Can I make the condensed milk dairy-free with coconut cream?
I've tested coconut cream as a swap and it works, but it's more finicky. Keep the heat lower than you would with heavy cream and don't rush it, or it separates on you. It takes an extra 5-10 minutes to reduce properly. The coconut flavor does come through, and it actually pairs well with the lime. I make it this way for my husband when he's avoiding dairy.
Why does the filling look wobbly when it comes out of the oven?
It's supposed to look wobbly. I pull mine when the edges are slightly set but the center still jiggles like jello. If you bake it until the center is firm, the texture will be off once it chills. The filling continues to set in the refrigerator, so trust the jiggle.
How long does this pie need to chill before serving?
I used to say 2 hours, but I've updated this to 4 hours minimum. At 2 hours, the center is still a little soft and the slices don't hold their shape. Reader Mia found the same thing when she tested it. Four hours gives you clean, picture-perfect slices. Overnight is even better if you have the time.
Can I freeze this pie?
I haven't had great results freezing it. The filling texture changes once it thaws, and it loses that silky quality that makes this version different. I make it 2-3 days ahead and keep it in the fridge instead. If you need a freezer-friendly keto dessert, my peanut butter pie holds up better in the freezer.
Which sweetener works best in the condensed milk, allulose or erythritol?
I've made it with both. Allulose stays smooth and doesn't crystallize, so the condensed milk has a better texture overall. Erythritol works but can leave a slight crunch if it doesn't fully dissolve during the simmer. My go-to is powdered allulose. If you only have erythritol, make sure it's powdered (not granular) and give it the full 30 minutes to simmer.
Can I use a no-bake method instead?
I've seen no-bake versions that use gelatin or extra cream cheese to set the filling. I haven't gone that route with this recipe because the baking step is what gives the filling its signature texture. The egg yolks and lime juice react with heat to create that silky set. Without baking, you're relying on gelatin, and in my experience it ends up tasting more like a mousse than a pie.
Will lime juice concentrate work instead of fresh limes?
I've only tested this with fresh-squeezed juice. Concentrate tends to taste flat and overly sweet compared to fresh, and since the lime flavor is the whole point here, I wouldn't cut corners. Four regular limes give you the 1/2 cup of juice you need. It takes me about 5 minutes to juice them.
The homemade sweetened condensed milk step looks intimidating but it's what makes this SO different from every other keto key lime pie I've tried. Those cream cheese versions always have that dense cheesecake thing going on. This one actually sets like a real pie. One thing I figured out though: four hours minimum in the fridge, not two. I pulled mine at two and the middle was still a little wobbly. Four hours and it sliced perfectly clean.
Updated the recipe card because of this. Four hours is the real answer, two is just technically set.
Brought this to a birthday dinner last weekend and my brother-in-law, who has strong opinions about keto food and shares them constantly, went back for a second slice and said nothing. The filling is insanely smooth for having no cream cheese in it. That homemade sweetened condensed milk makes all the difference.
Silent seconds from an opinionated person is the win. Cream cheese would've been easier but not nearly that smooth.
Made this for a small dinner party last weekend and one of the guests, who actually bakes her own desserts and is not keto, leaned over halfway through and asked what bakery the pie was from. When I told her I made it with almond flour crust and homemade sugar-free condensed milk, she looked genuinely confused in the best way. The lime filling is properly tart and smooth, nothing like the cream-cheese versions I've tried before. Bringing this to every dinner I go to now.
That bakery reaction is exactly why I put the condensed milk step in. Could've done cream cheese, would've been easier, but it would've tasted like it.
My husband has been dairy-free for about six months and has been missing out on every keto dessert I make. I'm determined to make this for him but I'm stuck on the filling because that homemade condensed milk is clearly the heart of it. Full-fat coconut cream is usually my go-to swap for heavy cream, but I've only ever used it in no-bake recipes, never in something where it's actually being cooked down and reduced. Does coconut cream behave the same way when you simmer it with the butter and sweetener, or does it get grainy and separate? The crust swap (vegan butter for regular) seems more straightforward, so mostly just trying to figure out if the filling is salvageable before I commit to making it.
Coconut cream works but it's more finicky. Keep the heat low and don't rush it or it'll separate. Reduces slower too, so add another 5-10 minutes. The coconut flavor that comes through is actually not bad with the lime.
Made this for my husband's birthday last week. He's been craving key lime pie since we started keto two years ago, and I was nervous about trying to replicate the real thing. The filling came out so smooth and tart, exactly like he remembered. He had two slices that night and told me it was better than the one from his favorite restaurant in the Keys. I'm already planning to make it again for our anniversary next month.
Two slices on his birthday and better than the Keys. That's high praise. The sweetened condensed milk swap is what gets people. Happy anniversary next month!
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.)
55 grams of fat in one slice. That's real sweetened condensed milk, not a cream cheese shortcut. Worth it.
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.
Oat flour won't work here. It doesn't crisp up at all, so the crust just melts. For the filling, did the condensed milk reduce enough before you added the lime juice? If it's still thin it won't set.
I have learned so much from you Annie oh, you've made a big difference in my life. I follow you everyday and enjoy all your videos everybody in my family loves your recipes thank you my dear!
Love hearing that. Glad the whole family is along for the ride.