The Key to a Perfect Key(to) Lime Pie: How to Make the Best Keto Lemon-Lime Ice Box Pie!

The Key to a Perfect Key(to) Lime Pie: How to Make the Best Keto Lemon-Lime Ice Box Pie!
Jump to Keto Lemon Lime Pie Recipe

This key lime pie is the perfect keto dessert! It is rich and creamy and sweet and tart all at once. The recipe uses HighKey snickerdoodle cookies to create an amazing low-carb keto-friendly “graham cracker” crust without too much fuss, and as a bonus it includes my homemade keto sweetened condensed milk that can be used to make all kinds of yummy desserts!

Key Lime Pie
Key(to) Lemon Lime Pie from

If you love this HighKey Cookie Crust you should check out my Perfect Keto Cheesecake, and for another fantastic recipe to use my homemade low-carb sweetened condensed milk check out these Keto Almond Joy Cookies!

Perfect Keto Cheesecake

Why You Will Love This Key Lime Pie

  • This crowd pleaser will not fail to impress your guests!
  • Bright, sweet, tart, citrus, flavor profile.
  • Bonus low-carb sweetened condensed milk recipe!
  • Low fuss crust that you can use to make cheesecakes, peanut butter icebox pies, and more!

What You Will Need

Let’s Make a Key Lime and Lemon Pie

To start with you will need to get the crust pre-baked and get sweetened condensed milk started. My keto sweetened condensed milk is made from just a few simple ingredients that you likely have in your refrigerator at this very moment. Heavy cream, butter, monk fruit sweetener (or your keto-friendly sweetener of choice), and vanilla (optional). The crust that I use for this recipe is made using a store bought cookie! It is a super easy, lazy, keto, cookie crumb crust that you are going to use again and again!

The milk takes a little bit of time, but it is well worth the effort. You will bring these ingredients to a gentle boil and then continue to babysit them like they are your favorite sister’s favorite child. Every few minutes a skin will form on top. Stir it back into the mixture and just continue to babysit and stir until it thickens up and has reduced by about half. Depending on the size of the batch this can take upwards of 40 minutes. The good news is that this can be done in advance and stored in the refrigerator for about a week or in an airtight container in the freezer for up to 4 months!

Sweetened Condensed Milk Recipe
sweetened condensed milk ingredients

Keto Sweetened Condensed Milk
This creamy, sweetened, condensed milk is low in carbs and keto friendly!
Prep Time 5 mins
Cook Time 35 mins
Total Time 40 mins
Course Condiments, Dessert
Cuisine American
Servings 12
Calories 156 kcal


  • 3 cups heavy cream
  • 3 tbsp butter
  • cup granulated monk fruit sweetener
  • 1 tsp vanilla extract optional


  • Add all of the ingredients to a skillet over medium heat except for the vanilla.
  • Bring to a boil, and then reduce the heat to a simmer. Simmer until the mixture has reduced by nearly half, stirring to prevent scorching. The end product should be thick and gooey.
  • If using vanilla, stir it in after removing the pan from the heat.
  • Allow the condensed milk to cool to room temperature.


Nutrition Information Per 1 Tbsp 
Calories: 156
Fat: 11g 
Net Carb: 1g
Protein: 1g 
Keyword dessert

While the sweetened condensed milk is cooling you can zest and juice your citrus and assemble and prebake your pie crust. For my pie I used a full cup of lemon and lime juice. We like our pie really tart! For the recipe I wrote for the masses I reduced the citrus juice to 3/4 cup, but if you are like me and you want a pie that bites back just a little bit use the whole cup! You can use a combination of lemon and lime like I did or rely on one or the other.

For this crust, I used HighKey snickerdoodle cookies. The cinnamon gives them a graham cracker-like flavor, and they have a great texture and taste. This is a yummy cookie for snacking too if you are a snacker like me! Crumb those puppies up in the blender add your melted butter (I always add some vanilla) and then press the whole mess into a pie plate or a springform pan.

There are no glutenous proteins in this to link up and give it structure! When you prebake the crust, with nothing in it to hold it up, it may start to slip and shrug. After the prebake stage, I simply took a spoon and used the back to press the crust back into place. As it cooled it hardened a bit and learned its place. Low-carb and keto baked goods can be delicate, so they sometimes need to be handled with care, but if you give them that little bit of extra loving care that they need they will return it to you tenfold!

Key(to) Lemon-Lime Pie Recipe
Key Lime Pie

Key(to) Lime Pie
This lemon-lime pie is a bright, tart, creamy, dessert that sits atop a keto "graham cracker" crust made from Highkey cookies! This a low-carb dieters delight!
Prep Time 35 mins
Cook Time 25 mins
Cooling Time 2 hrs
Total Time 3 hrs
Course Dessert
Cuisine American
Servings 12
Calories 437 kcal


HighKey Cookie Crust

  • 3 packages HighKey Snickerdoodles finely crumbed
  • 6 tbsp butter melted
  • 1 tsp vanilla

For the Filling

  • 1 recipe Keto Sweetened Condensed Milk see above
  • 3/4 cup lemon and lime juice
  • 5 egg yolks
  • 1 tsp lemon and lime zest


Keto Sweetened Condensed Milk

  • Prepare the condensed milk according to the recipe instructions. Allow it to cool to room temperature.

High Key Cookie Crust

  • Preheat the oven to 375°
  • Add the cookies to a blender or food processor and blend until finely crumbed. Add the melted butter and vanilla and stir or blend until well combined.
  • Press the mixture into a pie plate or springform pan.
  • Bake for 7 minutes. Remove from the oven and allow the crust to cool.

For the Filling

  • Preheat oven to 350°
  • Combine the cooled sweetened condensed milk, egg yolks, citrus juice, and citrus zest and stir until well combined.
  • Pour the mixture into the cooled, prepared, pie crust.
  • Bake for 20-25 minutes. The filling will still be jiggly. Allow cooling at room temperature for at least 30 minutes (I cooled mine for over an hour) Before placing it in the refrigerator for a minimum of 2 hours.


Nutrition Information Per 1 Slice:
Calories: 437
Fat: 44g
Net Carbs: 3.3g 
Protein: 5g 
Keyword keto key lime pie, keto pie, key lime pie, lemon-lime pie, pie

Let’s Eat!

This pie was such a hit when I served it at a dinner party at my mom’s house! I would love to see all of the pictures you snap when you serve this bad boy up! Head over to the Facebook group and SHARE SHARE SHARE, or check out my Pinterest page for more great content!

As always, happy snacking!

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