Key Lime Slab Pie

Pies & Tarts, Southern Desserts

This key lime slab pie is yummy and great for gatherings when you need more than a 9″. It’s sweet and tasty and will fly off the table.


Not only do I live in the South, I live in the “Sunshine State” of Florida. When you think of Florida, it brings to mind beaches, sunny days, and tasty delights. Desserts with a “citrus” flair are big hits down this way and particularly…the bold taste of Key Lime Pie.

In my grandmother’s last years, one of her favorite desserts was Key Lime Pie. She found a frozen pie she liked at the store and kept it in her freezer. She would take it out, cut a slice, and share with my little ones. They ALL LOVED IT!

None of them cared that it was “store bought”. They just liked the rich, decadent taste of lime in a creamy and smooth pie.

If my Mema were alive today, I think she would really enjoy this Key Lime Slab Pie. So..Mema…this one is for you!

Psst… you’ll also love our peach crumble slab.

key lime slab pie with shipped cream and graham cracker crust on white table

Substitutions for the key lime slab

This dessert is rich and tropical just as it is, but if time is an issue, there are some substitutions that would save you some minutes on the clock. You could purchase several “store bought” graham cracker crusts and food process them for the crust layer.

However, they tend to be dry and can crumble. Most often the reason a crust crumbles is that it isn’t moist enough. Use melted butter or a mild olive oil to moisten the crumbs.

Another trick is to brush the crust with an egg wash and bake it for 10 minutes. Let it cool, fill and then bake per the key lime slab directions. The egg wash keeps the crust from getting soggy.

If making your own whipped topping is going to add unnecessary time to your prep, substitute Cool Whip topping. It is light and fluffy and looks heavenly on top of a pie! And it tastes good…most people love it!

key lime slab pie with key limes and whipped cream

What types of pans can you use or slab pies?

The best pan for a slab pie is a 10 x 15 inch jelly roll pan or a rimmed, rectangular pan. This type of pan will allow you fill it to the brim with crust and filling.

It makes a large pie and when cut, the pie comes out in perfect little bars or “slabs”.

pouring key lime pie batter into a graham cracker crust on a jelly roll pan

What you need…

Ingredients

To make your slab pie, you will need a Graham Cracker Crust which includes -3 ½ cups crushed graham cracker crumbs (about 25 whole graham crackers), ¾ cup butter + 2 tablespoons butter (melted), ¼ cup brown sugar, and ¼ cup white sugar.

For your Key Lime Filling -prepare 3 cups sweet condensed milk, 6 egg yolks, 1 cup of key lime juice, and
4 tablespoons grated lime zest (separated). Mix together until smooth and creamy.

Finally, you will need the ingredients for your Whipped topping– 1 cup heavy cream, ½ cup powdered sugar, and one tablespoon lime zest whipped up to make a decadent and fluffy topping.

slab pie crust in a jelly roll pan

How to make this

Directions

Preheat oven to 350 degrees F. Spray 10 x 15 inch pan with baking spray, then set aside.

For the Crust: Pulse graham crackers in a food processor until finely chopped. Then in a bowl mix together butter, graham cracker crumbs, and sugar. Then firmly press mixture into 10 x 15 into the pan. Bake the crust for 10 minutes. Then allow the crust to cool completely.

For the Key Lime Filling: In a medium bowl combine sweetened condensed milk, eggs,
lime juice, and 2 tablespoons lime zest. Mix well and pour into the cooled graham cracker crust. Bake in a preheated oven for 10 minutes until small bubbles appear.

DO NOT OVER BAKE. Pie will be slightly jiggly. (increase amount of time in small increments if needed). Cool completely.

Topping: Garnish with whipped cream, fresh lime slices, and lime zest.

key lime pie on white plate with lime zest shavings

Other desserts we love around here!

Here are some of our other favorite slabs…

key lime slab pie

Key Lime Slab Pie

Rachel Norman
This key lime slab pie is yummy and great for gatherings when you need more than a 9". It's sweet and tasty and will fly off the table.
4.60 from 20 votes
Prep Time 10 minutes
Cook Time 10 minutes
Crust prep 20 minutes
Total Time 40 minutes
Course Dessert
Cuisine Southern
Servings 12 people
Calories 580 kcal

Ingredients
  

Graham Cracker Crust

  • 3.5 cups graham cracker crumbs (about 25 whole graham crackers)
  • 3/4 cups butter plus 2 tbsp., melted
  • 1/4 cup brown sugar
  • 1/4 cup white sugar

Key Lime Filling

  • 3 cups sweetened condensed milk
  • 6 each egg yolks
  • 1 cup key lime juice
  • 4 tbsp lime zest grated and separated

Whipped Topping

  • 1 cup heavy cream
  • 1/2 cup powdered sugar
  • 1 tbsp lime zest

Instructions
 

  • Preheat oven to 350 degrees F. Spray 10 x 15 inch pan with baking spray, set aside.

Graham Cracker Crust

  • Pulse graham crackers in a food processor until finely chopped.
  • In a bowl mix together butter, graham cracker crumbs and sugar.
  • Press mixture into 10 x 15 in pan, use the bottom of a measuring cup to press the crust into the pan.
  • Bake the crust for 10 minutes, allowing the crust to cool completely.

Key Lime Filling

  • In a medium bowl combine sweetened condensed milk, eggs, lime juice, and 2 tablespoons lime zest.
  • Mix well, pour into cooled graham cracker crust.
  • Bake in a preheated oven for 10 minutes until small bubbles appear, DO NOT OVER BAKE. Pie should be slightly jiggly. (increase amount of time in small increments if needed).
  • Cool completely.

Whipped Topping

  • Whip heavy cream and powdered sugar together until stiff peaks form.
  • Garnish the top of the pie slab with the whipped topping and decorate with fresh lime slices and lime zest.

Nutrition

Calories: 580kcalCarbohydrates: 76gProtein: 8gFat: 28gSaturated Fat: 16gCholesterol: 89mgSodium: 370mgPotassium: 375mgFiber: 1gSugar: 61gVitamin A: 868IUVitamin C: 9mgCalcium: 260mgIron: 1mg
Keyword lime
Tried this recipe?Let us know how it was!

17 Comments

  1. 5 stars
    Easy to follow, first time making and won’t be the last. Made for husband’s Men’s Ministry event. At intermission he passed along “One of the men just told me, “If you put that key lime pie dessert on your head, your tongue will beat your brains out trying to get to it.”
    High praises.” Thank you so much for a hit!

  2. Making the graham cracker crust why do you add brown sugar and white sugar for the key lime slab dessert!?

  3. Can I make your lovely lime slab pie a day before my event?

    Thank you for the recipe

  4. Can I halve this recipe in order to use a smaller pan?

  5. Made it. Looked perfect. Tried covering it and the tinfoil and siran wrap both stuck to it and ruined it! How do you cover and transport?

    • Avatar photo

      Oh gosh, sorry to hear. The pan I use is deep enough that when I cover it in foil it doesn’t touch the cake or its topping. Another option, if possible/practical, is to hold off on adding the whipped topping until you arrive at your destination.

  6. What a great recipe for me to try with our Minnesota Persian lime tree.
    It is about 7-8 years old started with a casually tossed seed in a pot of ivy!
    We have diligently wintered and summered it and have about 30+ limes to harvest this year.
    I may drizzle a thickened raspberry coulis on top of whipped cream decorative topping for church gathering this coming Sunday.
    You have a lovely repertoire of recipes on your happening site … thank you, Sara.
    My best,
    Viking Warrior Woman who escaped Florida back to my Midwest home!

  7. Belinda Castillo

    I’m confused about the sugar too. The recipe says both sugars in crust. But you responded to a previous question stating the white sugar was in the filling? That’s not what the recipe says. Can you clarify?

    • Avatar photo

      Belinda, thanks so much for the question. I’ve edited my other comment to correct the typo. The key lime filling is in fact sweetened by just the sweetened condensed milk. For the crust, we use half brown sugar and half white sugar, but you could use one or the other if you don’t happen to have both.

  8. 5 stars
    Made this for a work BBQ & got rave reviews.

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