Recipes | Pies & Tarts

Low FODMAP “Key” Lime Pie


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Do you like Key lime pie? You are going to LOVE our Low FODMAP “Key” Lime Pie, tangy, creamy and resplendent in a crispy crust. Why the quotes around “key”? Because a long time ago when I was working on a version for my book Unforgettable Desserts and baking pies for my bakery, I learned something…

overhead image of low FODMAP Key Lime Pie in pie plate

I Like Persian Limes

Persian limes are the limes that you typically buy in the supermarket. We are used to their level of tartness and they provide what we have come to think of as “lime” flavor.

When it comes to “Key” lime pie, I am looking for just the right balance of tart and sweet. And after doing side by side taste tests, using Key lime juice and Persian lime juice, I decided that I liked the Persian lime juice results much more. I like my lime desserts tart and I find the Persian juice to be tarter.

overhead shot of Low FODMAP "Key" Lime Pie on white platter

Now, I don’t want any Key West residents hammering away at me. I know that if I do not use Key limes to make this pie that it is not properly a “Key” lime pie; hence the quotes.

But I am calling this Low FODMAP “Key” Lime Pie because if I call it a Lime Pie, no one will find it using Google searches. So, mea culpa.

Overhead key lime pie in dish with silver server

Sour Is Good

Some folks have questioned my taste buds and insist that the key limes are tart-er.

The folks at Cook’s Illustrated agreed with me and reported that in their formal tastings they found the Key lime juice to be slightly less tart and lab tests confirmed their impressions. The Persian limes showed a lower pH, indicating higher acidity, than the Key lime juice.

Numbers Count

Key limes are also much smaller than Persian limes and you would probably need about two-dozen to get the job done for our recipe. With the Persian limes, we can buy half a dozen, and know that you will have enough for juice and zest.

Let’s Talk Sweetened Condensed Milk

The classic Key lime pie uses sweetened condensed milk for the majority of sweetening (except for the sugar in the whipped cream topping) and for the dairy in the pie filling itself.

On the Monash app you will see two entries for sweetened condensed milk. The U.S. entry says 1 teaspoon is low FODMAP, while the entry for sweetened condensed milk from Malaysia is low FODMAP at 1 Australian tablespoon. Why the discrepancy? We do not know.

This is the main reason why, up until now, I had not developed a Low FODMAP Key Lime Pie. But, after playing with our DIY approach to making our own lactose-free dairy, I decided it was time.

Making Your Own Lactose-Free Dairy

DIY dairy tools

No, I am not suggested you have to milk a cow. But you will need some extra tools. As described in our article, DIY Lactose-Free Dairy, you will need two things:

  1. Lactase enzyme drops, such as Lacteeze Drops
  2. Glucose-testing strips

PLEASE read the DIY article for a complete explanation of how to use these tools and why we think you can make our own lactose-free sweetened condensed milk.

You will be adding  lactase-enzyme drops to your sweetened condensed milk, let it sit overnight, and then you will be testing the sweetened condensed milk with the glucose-testing strips.

The success of whether you get a lactose-free batch will be dependent on how much enzyme you use, how well you combine the sweetened condensed milk with the enzyme and the length of time you allow the mixture to sit. If at first the strip does not show you that your batch has converted, then start again with more drops. All of this will make sense once you have read the article.

A Lot Of Work For A Pie

Yes, I realize that this is a lot of work to do for a pie. And at the very least you are going to have to start a day ahead, allowing the sweetened condensed milk to sit overnight, but this recipe is aimed at those of you who REALLY miss having Key lime pie and are willing to put in the time and effort.

What About The Whipped Cream?

The amount of whipped cream per serving is considered low FODMAP, so no worries there! If you can find lactose-free heavy cream to make your whipped cream, go for it, but you can use conventional heavy cream.

Graham Cracker Crust

The crust is made from a fantastic gluten-free cookie – Enjoy Life Crunchy Mini Cookies in Vanilla Honey Graham. Now before you think “honey”! That’s not low FODMAP! Rest assured that this product, along with several others from Enjoy Life, has been lab tested and Certified Low FODMAP by FODMAP Friendly.

Box of Enjoy Life mini Vanilla Honey Grahams

That’s right! No worries at all –they are crispy, crunchy and while they make a great snack, we wanted to see if we could bake with them. In fact, they were the inspiration for this recipe.

And you can read more about Enjoy Life and all of their Certified Low FODMAP Products in our exclusive interview.

You can purchase all of Enjoy Life Low FODMAP Certified Products here in our Amazon Low FODMAP Shop! 

As you can see below on the left-hand side of the cookie bag label, it explains part of the company’s promise to be free from many allergens.

Label of Enjoy Life mini Vanilla Honey Grahams

Now let’s look at the ingredients needed to make this stunning pie and also look at some step-by-step photos to help you during the process.

Ingredients For Low FODMAP “Key” Lime Pie

Ingredients for Key Lime PieHow To Make Low FODMAP “Key” Lime Pie

You have to obtain your Lactase enzyme drops, such as Lacteeze Drops, and your glucose testing strips before beginning. Then, the day before you want the pie, you have to prepare your sweetened condensed milk, making it lactose-free. You could even do this 2 days ahead.

The crust is easy as long as you grind the cookies evenly and finely. I use a food processor fitted with a metal blade.

cookie crumbs ground finely in food processorThen combine the cookie crumbs with the melted butter,

cookie crumbs combined with melted butter

…then press into a 9-inch (23-cm) ovenproof glass pie plate. I like Pyrex.

cookie crumb crust in pie plate

Bake the crust until light brown and crisp.

The filling is then easily made by whisking the treated sweetened condensed milk together with the lime juice, lime zest and egg yolks.

making filling for low FODMAP key lime pie

Make sure to use a rasp style zester/grater to create very fine textured lime zest as seen below.

using a Microplane zester to create very fine zest

Once baked, you can simply dollop whipped cream on top, or use a piping bag and star tip, such as a Wilton 1M. My favorite star tip! You will use it for everything! It makes the best frosting swirls on top of cupcakes.

1M tip

The lime slices as garnish are optional.

Low FODMAP Key Lime Pie Closeup

For another recipe featuring Enjoy Life products, check out our Low FODMAP Banana Chocolate Chip Muffins.

And for another taker on “key lime”, try our cupcakes!

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overhead image of low FODMAP Key Lime Pie in pie plate
5 from 2 votes

Low FODMAP "Key" Lime Pie

Do you like Key lime pie? You are going to LOVE our Low FODMAP “Key” Lime Pie, tangy, creamy and resplendent in a crispy crust.

Makes: 12 Servings
Prep Time: 15 minutes
Cook Time: 10 minutes
Chilling Time: 8 hours
Author: Dédé Wilson


Vanilla Honey Graham Crust:

Filling & Topping:

  • 4 large egg yolks
  • 2/3 cup (165 ml) freshly squeezed lime juice made from Persian limes
  • 2 teaspoons very finely grated lime zest
  • 3/4 cup (180 ml) lactose-free heavy cream, chilled
  • Scant 1 tablespoon confectioners’ sugar
  • Piping bag and star tip
  • 2 extra limes for garnish; optional


  1. Making The Lactose-Free Sweetened Condensed Milk: Thoroughly whisk together the sweetened condensed milk with 12 Lacteeze drops. Cover with plastic wrap and let sit overnight. Test with glucose testing strips and proceed if you get proper results.

  2. Make The Crust: Position rack in center of oven. Preheat oven to 375°F (190°C). Coat the inside of a 9-inch (23 cm) ovenproof glass pie plate with nonstick spray; set aside. Grind the cookies to a fine, even texture in a food processor using a metal blade. Combine in a bowl with melted butter. Press into the prepared pie plate in an even layer. Bake for about 8 to 10 minutes or until dry and crisp and light golden brown. Lower oven to 350°F (180°C).

  3. Meanwhile, make the filling. Whisk the egg yolks, lime juice and zest into the prepared sweetened condensed milk. Pour this mixture into the pre-baked crust and bake for about 15 minutes or until filling is set but still faintly jiggly in the center. Cool on rack until barely warm, then refrigerate for at least 4 hours or overnight.

  4. Make the topping by beating the cream and confectioners’ sugar until stiff peaks form; do not overbeat. Use piping bag and star tip to make 12 rosettes around the outer edge and one in the middle. Garnish with thin limes slices, if using. Serve immediately or the pie may be refrigerated for up to 1 day at this point. Serve chilled.



FODMAP Information

Our recipes are based on Monash University and FODMAP Friendly science.

  • Eggs: Eggs are high in protein and do not contain carbohydrates, according to Monash University.
  • Lime Juice: Monash University has lab tested lime juice and it is low FODMAP in 1 cup (250 g) amounts (double that of lemon juice, as an interesting fact).
  • Sugar: Monash University and FODMAP Friendly have both lab tested white, granulated sugar. Monash states that a Green Light low FODMAP serving size of white sugar is ¼ cup (50 g). FODMAP Friendly simply states that they have tested 1 tablespoon and that it is low FODMAP. Regular granulated white sugar is sucrose, which is a disaccharide made up of equal parts glucose and fructose. Sucrose is broken down and absorbed efficiently in the small intestine.

Please always refer to the Monash University & FODMAP Friendly smartphone apps for the most up-to-date lab tested information. As always, your tolerance is what counts; please eat accordingly. The ultimate goal of the low FODMAP diet is to eat as broadly as possible, without triggering symptoms, for the healthiest microbiome.

Course: Dessert
Cuisine: American


Calories: 287kcal | Carbohydrates: 30g | Protein: 4g | Fat: 15g | Fiber: 1g | Sugar: 1g

All nutritional information is based on third-party calculations and should be considered estimates. Actual nutritional content will vary with brands used, measuring methods, portion sizes and more. For a more detailed explanation, please read our article Understanding The Nutrition Panel Within Our Recipes.

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