Key Lime Pie with Speculoos Crust

February 22, 2022marissamakes

Prep time: 20 minutes

Cook time: 20 minutes

Serves: One 9" pie

Key lime pie is an American classic. Rich, creamy, and full of the bright flavor of key limes, it’s both easy to make, and a delight to eat. This version uses sour cream to aid in richness, and makes this dessert an absolute cinch to make.

What are Key limes, and where do I find them?

Key limes, also known as Mexican limes, or West Indies limes, are a variety of lime that is much smaller in size than the more common Persian lime. They are more fragrant, with a thinner rind and more seeds, and turn yellow when they’re ripe. Commonly found in Florida, which is why they have earned the name of Key limes due to association with the Florida Keys, these little limes pack a real flavor punch, and are the traditional type of lime used in this American classic.

If you don’t happen to live in Florida, you can sometimes find Key limes under the name of Mexican limes at the grocery store. You can also often find them at farmers’ markets, sold by specialty citrus producers. If you live in Los Angeles, like I do, there are several producers that sell Key limes at the Hollywood Farmer’s Market.

If you can’t find Key limes anywhere in your area, you can substitute the Key limes used in this recipe for Persian limes. That said, I really recommend you try and track some down, so you can enjoy that traditional flavor!

Okay… so then what is speculoos?

Speculoos is a type of Belgian spiced cookie. It has a lightly spiced, almost caramelized flavor that makes it perfect for cookie based crusts for pies and cheesecakes. Key lime pie is traditionally made with a graham cracker crust. However, I think the added complexity of the speculoos cookies really gives this recipe an extra layer of deliciousness.

You can find speculoos cookies at Trader Joe’s. They are also sold by Lotus brand under the name of Biscoff. Give them a try! You’ll never want to use a plain graham cracker crust ever again.

How to make the perfect Key lime pie

Key lime pie is an impressive dessert, with lots of decadent flavor. It’s also incredibly easy to make. Though the most traditional recipes call for an egg custard, I’ve found that sour cream is a wonderful substitute. It also cuts down the active time.

The crust for this pie is a simple mixture of speculoos crumbs, brown sugar, and butter. I used a 9″ loose bottomed tart pan, but you could also use a shallow ceramic pie dish, or traditional metal pie tin. Simply add the crust mixture to your tin of choice in an even layer, and bake for 8 minutes. My pro-tip for getting an even cookie crumb crust is to pack it in to the tin using the flat bottom of a glass or jar. Much easier than pie dough!

The filling for the pie is just as simple to whip up. Start by juicing your limes. This recipe calls for 3/4 cup of lime juice, which you should get from about 15 Key limes. Combine the juice with the condensed milk, sour cream, and lime zest. I like to use a Danish Dough Whisk to mix the filling for this pie, because it removes all lumps without incorporating too much air. A silicone spatula would work nicely as well.

Bake the pie for about 10 minutes, then allow it to cool in the fridge for 2-3 hours. Serve this Key lime pie cold, topped with freshly whipped cream and slices of lime. If you want to go all out, you could even top it with Italian meringue, like in my recipe for my Meyer Lemon Italian Meringue Pie .

Sound easy? That’s because it is! But make no mistake, for what this pie lacks in active work, it makes up in flavor in a big way.

How to store this pie

This Key lime pie keeps well in the fridge, covered tightly, for 3-5 days.

I hope you give this Key Lime Pie with Speculoos Crust a try! Be sure to tag me on instagram so I can see your bakes, and leave me a comment below! Your feedback helps other bakers who are giving this recipe a try, and I love hearing about your bakes!

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  • Prep time: 20 minutes
  • Cook time: 20 minutes
  • Total time: 3 hours 40 minutes
  • Serves: One 9" pie

Key lime pie is an American classic. Rich, creamy, and full of the bright flavor of key limes, it's both easy to make, and a delight to eat. This version uses sour cream to aid in richness, and makes this dessert an absolute cinch to make.


For the pie crust

  • One 7oz packet speculoos cookies , (200g)
  • 1/4 c brown sugar, (55g) packed
  • 6 tbsp unsalted butter, (90g) melted

For the filling

  • 3/4 c Key lime juice, (200ml), from about 15 Key limes
  • 1/2 c full fat sour cream, (120g)
  • 28 oz sweetened condensed milk, (two 14 oz cans)
  • 2 tbsp Key lime zest

For the topping

  • 1 c heavy whipping cream, (240ml)
  • 2 tbsp powdered confectioner's sugar
  • lime slices, for garnish


Make the crust

  • 1)

    Preheat the oven to 375 degrees F. In a food processor or blender, pulse the speculoos cookies until you have fine crumbs. Add the sugar, and pulse to combine. Stir in the melted butter.

  • 2)

    In a 9″ loose ring tart pan or pie plate, evenly distribute the crumb crust and pack it down using a flat bottomed glass or measuring cup. Take care to push it up about 1″ around the sides, to create the outer crust.

  • 3)

    Bake the crust for 8 minutes or until it just begins to darken in color. Remove from the oven and allow to cool for a few minutes.

Make the filling

  • 1)

    In a large bowl, combine the Key lime juice, sour cream, zest, and condensed milk with a spatula. Stir until smooth, but take care not to incorporate air while mixing, or this will result in bubbles, rather than a smooth filling.

  • 2)

    Add the filling to the slightly cooled shell, using an offset spatula to smooth the top.

Bake the pie

  • 1)

    Bake the pie for 8-10 minutes, or until the filling has just set. It should still have a gentle wobble in the middle. Remove from the oven and allow to cool before chilling in the fridge for 2-3 hours.

Garnish the pie

  • 1)

    Just before you are ready to serve, make the whipped cream. In the bowl of a stand mixer, or using electric beaters, whip the cream and powdered sugar together until it reaches soft peaks.

  • 2)

    Pipe or spoon the whipped cream onto the pie, as desired. Decorate with lime slices and additional lime zest.


If you can’t find Key limes, substitute the 3/4 cup of Key lime juice for regular lime juice. You will not need to juice as many limes, if you are using the Persian variety.

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