Key Lime Slab Pie

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This Key Lime Slab Pie is creamy, luscious, refreshing, and delicious. It’s the perfect dessert to make when you need to feed a crowd and will become a favorite.

Key Lime Slab Pie is a creamy, refreshing pie full of lime flavor with a graham cracker crust.

Hey everyone, Jodi here from 5 Boys Baker sharing one of my favorite spring/summer treats with you. This Key Lime Slab Pie is what my dessert dreams are made of! I love all things lemon and/or lime and can’t wait to start baking away when spring rolls around.

Of course, living in Utah you never know when that might be. I could mow my lawn one day and must snow blow the next. Utah weather is so bi-polar.

Now, I have a bit of a confession to make. I am a cookbook/cooking magazine junkie. I own more cookbooks and cooking magazines than I can count. I can’t seem to walk out of Costco or Sam’s Club without a cooking magazine. It’s a bit of a problem because I’m running out of space for them all. I’ve resorted to my upstairs linen closet to store some of them.

Key Lime Slab Pie is a creamy, refreshing pie full of lime flavor with a graham cracker crust.

If it wasn’t for this little addiction I have, I never would have discovered this Key Lime Slab Pie because it’s from one of those cooking magazines I bought (Taste of the South Southern Pie & Icebox Desserts 2015).

This Key Lime Slab Pie is so, so good! It has the perfect balance of tartness and sweetness, and the graham cracker crust is a winner here, its thick, buttery, and seriously makes this pie even all the more delicious.

This is the perfect dessert for the spring and summer months ahead. It’s simple to make, but make sure you plan because it does need to chill for several hours. I sent some of this into work with my husband and when he got home that night, he told me his business partner said this one was a keeper. Hopefully you’ll agree.


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Key Lime Slab Pie
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5 from 4 votes

Key Lime Slab Pie

Course Dessert
Author Holly



  • 3 ½ cups graham cracker crumbs (about 25 whole graham crackers)
  • 3/4 cup plus 2 Tablespoons melted butter
  • 1/2 cup granulated sugar


  • 1 cup granulated sugar
  • 6 tablespoons cornstarch
  • 1/4 teaspoon kosher salt
  • 2 cups whole milk
  • 4 large egg yolks
  • 1 tablespoon lime zest
  • 1/2 cup fresh lime juice
  • 2 tablespoons butter


  • 2 cups heavy whipping cream
  • 3/4 cup powdered sugar
  • 1/4 cup fresh lime juice


  • Preheat over to 350 degrees F. Spray a 15×10-inch jelly roll pan with cooking spray. Set aside.
  • For Crust: In a large bowl mix together the graham cracker crumbs, melted butter and sugar. Pour crumb mixture into prepared pan and evenly spread. Use the bottom of a measuring cup to press the mixture firmly down and up the sides of the pan. Bake 10 minutes. Let cool on a wire rack.
  • Filling: In a large saucepan whisk together the sugar, cornstarch and salt. Whisk in the milk and bring to a boil over medium heat, stirring constantly, continue cooking 2 minutes. Remove from heat. Put the egg yolks into a medium bowl and slowly whisk some of the hot milk mixture into the egg yolks (I whisk in about 1 cup). Pour the egg yolk mixture back into the pan with the remaining milk mixture. Cook, whisking constantly, until thick and bubbly, about 3 to 4 minutes. Remove from heat and stir in lime zest, lime juice and butter. Pour into a large bowl and place a piece of saran wrap right up against the top of the mixture. Put in refrigerator and cool completely.
  • Once mixture is cool, pour into prepared crust and spread evenly.
  • Topping: In a large bowl, beat whipping cream, powdered sugar and lime juice on high until still peaks form. Spread topping over lime filling and refrigerate at least 4 hours. Cut into desired size bars and serve. Store in refrigerator.
  • *Notes: The original recipe calls for bottled key lime juice, but I always just use fresh lime juice (not key limes, they’re so small and take way too many to get enough juice out of). Feel free to use the bottled key lime juice or just use regular limes.
  • Also, I don’t usually buy whole milk, but I always half & half in my fridge so to save me a trip to the store, I use 1 cup half & half and 1 cup milk (1%) for the filling.


Recipe by: 5 Boys



Slab Pie with Lime flavors
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6 thoughts on “Key Lime Slab Pie

  1. 5 stars
    Living in Southwest Florida, we make key lime pie a lot ! Trying your recipe for a crowd was great. Everyone LOVED it… including picky 7 and 11 yr. olds, as well as my husband who does NOT like key lime pie !! Your website has now become my favorite go to for fun, delicious recipes. Thank You !!

  2. 5 stars
    So easy to make, Served today at luncheon. I substituted stevia for the sugar in the crust mixture, saved a few calories and definitely Yummy!

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