Ultimate Coconut Key Lime Pie Cake: A Tropical Delight for Any Occasion

As the holiday season approaches, bringing with it the warmth of gatherings and the aroma of delicious food, there’s so much to be thankful for. And truly, my journey in baking and sharing these creations wouldn’t be possible without you, my wonderful readers! Your enthusiasm for trying my recipes, like this extraordinary Coconut Key Lime Pie Cake, fuels my passion and inspires me to keep creating.

While Thanksgiving often conjures images of pumpkin and pecan pies, why not surprise your guests with something uniquely refreshing this year? This Coconut Key Lime Pie Cake offers a delightful twist on traditional holiday desserts, bringing a burst of tropical sunshine to your table. It’s a harmonious blend of tangy, sweet, and wonderfully rich flavors, sure to become a new family favorite.

Decoding the Coconut Key Lime Pie Cake Phenomenon

This isn’t just any cake; it’s an experience. Imagine all the beloved elements of a classic key lime pie—the zesty, creamy filling, the distinct tang, the crumbly crust—transformed into an elegant, layered cake. But we don’t stop there! We infuse it with the delicate, sweet essence of coconut, elevating it to an entirely new level of deliciousness. It’s truly a mouthful, both in name and in flavor, promising a delightful interplay of textures and tastes.

The beauty of this recipe lies in its ingenious combination. We take the bright, citrusy punch of key lime and pair it with the tropical sweetness of coconut, all nestled within a tender cake and a crunchy graham cracker base. This cake isn’t just a dessert; it’s a conversation starter, a celebratory centerpiece, and a testament to innovative baking. Whether you’re a devout fan of key lime pie, a coconut enthusiast, or simply someone looking for an exciting new dessert, this cake delivers on every front.

The Foundation: A Perfectly Crunchy Graham Cracker Crust

For me, the graham cracker crust is a textural masterpiece and perhaps the most underrated component of this cake. In a dessert often characterized by its softness, that delightful crunch from the crust provides a wonderful contrast that truly elevates each bite. It’s not just a base; it’s an integral part of the overall experience, adding depth and a satisfying mouthfeel.

Crafting this crust is straightforward, much like any traditional graham cracker crust, but with a crucial difference: it’s baked directly into your cake pans before adding the cake batter. This ensures a sturdy, flavorful foundation that holds up beautifully to the moist cake layers and tangy lime curd. Simply combine finely crushed graham cracker crumbs with melted unsalted butter, a touch of granulated sugar, and a pinch of salt. The salt helps to balance the sweetness and brings out the nutty flavor of the graham crackers.

After mixing, press the mixture firmly and evenly into your prepared cake pans. I recommend using the back of a measuring cup or a flat-bottomed glass to ensure a compact and uniform crust. A quick 9-minute bake at 375°F (190°C) is all it takes to set the crust, giving it that perfect golden hue and irresistible aroma. Let it cool completely before adding your cake batter; this prevents the crust from becoming soggy and maintains its delightful crispness. This small step makes a huge difference in achieving that beloved crunch that makes this cake so special.

The Star: Moist Coconut Lime Cake Layers

The cake layers themselves are the heart of this tropical creation. Building on a beloved coconut lime cake recipe, I’ve refined it specifically for this pie-cake hybrid. The key to its incredible flavor and tender texture lies in the careful selection of ingredients and precise execution. We start with a rich butter-sugar base, ensuring a moist and fluffy crumb that melts in your mouth.

For a truly exceptional coconut flavor, I rely on both canned coconut milk and a high-quality coconut emulsion (Lorann’s is my go-to). The coconut milk provides essential moisture and a subtle, natural coconut taste, while the emulsion intensifies that tropical essence without adding excess liquid. This dynamic duo ensures every bite is infused with authentic coconut goodness. But what truly makes these layers shine, especially in this “Key Lime Pie” context, is the generous addition of fresh lime zest. While the original coconut lime cake was fantastic, for this pie cake, we need that lime flavor to truly *pop*. The zest provides essential aromatic oils and a vibrant, concentrated citrus punch that beautifully complements the coconut.

When mixing, be mindful not to overmix the batter once the flour is added. Overmixing can lead to a tough cake, and we want nothing less than a light, airy, and moist crumb. Alternate adding the dry ingredients with the coconut milk, mixing just until combined. This technique ensures a perfectly tender cake that forms the ideal canvas for our luscious lime curd and creamy coconut buttercream. Each layer is baked to perfection on top of the pre-baked graham cracker crust, resulting in a cohesive, flavorful, and structurally sound dessert.

The Tangy Heart: The Best Lime Curd You’ll Ever Make

Yes, calling it “the best” is a bold statement, but if you’ve tried any of my recipes before, you know I stand by it! This lime curd is unbelievably easy to make and yields an incredibly bright, intense lime flavor that is absolutely essential for this cake. It’s the vibrant, tangy core that ties all the other elements together, providing that characteristic key lime pie punch.

Achieving a perfect lime curd involves a few simple steps and a bit of patience. The combination of fresh lime juice, abundant lime zest, sugar, whole eggs, and egg yolks creates a luxurious, silky-smooth filling. Cooking it over medium-high heat, while constantly whisking, is key to preventing the eggs from scrambling and ensuring a smooth, thick consistency. Watch for it to bubble gently for a few minutes before removing it from the heat. The final touch of butter whisked in off the heat adds richness and a beautiful gloss.

Now, let’s talk about color! While completely optional, a hint of green food gel can transform your curd visually. I’ve made the mistake of adding too much coloring, only to end up with something neon green rather than delicately vibrant. Remember, a little goes a very long way! I always recommend using a gel food coloring, like Americolor (Leaf Green is my preferred shade), and applying it sparingly with the tip of a toothpick. You can always add more, but you can’t take it away. Aim for a subtle, natural lime-green hue that hints at the fresh flavors within. Once made, straining the curd through a fine-mesh sieve ensures ultimate smoothness, removing any bits of zest or cooked egg. Pressing plastic wrap directly onto the surface of the warm curd prevents a skin from forming as it cools, resulting in a perfectly smooth texture ready for assembly after a few hours in the refrigerator.

Creamy Perfection: The Coconut Buttercream

No layered cake is complete without a luscious frosting, and for this Coconut Key Lime Pie Cake, a light and fluffy coconut buttercream is the ideal choice. This buttercream doesn’t just hold the layers together; it’s a crucial component that balances the tartness of the lime curd and enhances the tropical notes of the cake. Its creamy texture provides a smooth contrast to the crunchy graham cracker crust and the tender cake layers.

Made with slightly cold unsalted butter, sifted powdered sugar, heavy whipping cream, coconut emulsion, and a pinch of salt, this buttercream is both rich and airy. Beating the butter first to cream it helps to create a soft, smooth base. Then, adding the dry and liquid ingredients and starting on low speed ensures everything is well combined without a cloud of sugar dust. The magic happens when you turn the mixer to medium-high speed and beat it for several minutes. This process incorporates air, making the frosting light, fluffy, and visibly whiter. Don’t skip scraping down the bowl to ensure even mixing. For an extra-smooth finish, especially before spreading, give the buttercream a final beat with a wooden spoon or rubber spatula to eliminate any trapped air bubbles.

This coconut buttercream is not only delicious but also wonderfully pipeable, making it perfect for creating a decorative border around the lime curd in each layer, preventing it from oozing out. If you plan on doing elaborate piping on top, I recommend making 1.5 times the recipe to ensure you have plenty to work with. The sweet, tropical notes of the buttercream perfectly complement the zesty curd and the coconut-lime cake, creating a harmonious symphony of flavors in every bite.

Assembly and Make-Ahead Magic

Bringing all these delightful components together is the final, rewarding step. Ensure your cake layers are completely cooled and, if needed, leveled for a perfectly even stack. Start by securing your first cake layer, graham cracker crust side down, to your cake board with a small dollop of buttercream. This prevents any shifting during assembly or transport.

Next, use a piping bag to create a dam of coconut buttercream around the edge of the first cake layer. This clever trick creates a barrier to hold the generous layer of tangy lime curd firmly in place, preventing it from seeping out the sides. Spoon about a third of a cup of the chilled lime curd into the center and gently spread it to the buttercream dam. Repeat this process with the second cake layer, adding another ring of buttercream and a layer of curd. Finally, place the last cake layer, crust side down, on top.

Once assembled, apply a thin layer of coconut buttercream all around the cake. This is your “crumb coat,” essential for trapping any loose crumbs and creating a smooth canvas for your final frosting layer. Pop the cake into the freezer for about 15 minutes to firm up the crumb coat. This quick chill makes applying the final layer of buttercream much easier and ensures a pristine finish. After the crumb coat is set, apply the remaining coconut buttercream, decorating as desired. For a beautiful presentation, you can garnish with toasted coconut flakes, thin lime slices, or a sprinkle of graham cracker crumbs. This cake is best served at room temperature, allowing all the flavors and textures to fully shine.

Perfect for Thanksgiving, and Beyond!

This Coconut Key Lime Pie Cake is truly perfect for Thanksgiving, offering a refreshing alternative to the usual autumn flavors. However, its vibrant, tropical profile makes it a fantastic dessert for any occasion, from summer barbecues to spring brunches, or simply a weekend treat. Its bright flavors are a welcome addition at any time of year.

The best part about this show-stopping cake? Its incredible make-ahead potential! To save valuable time during busy holidays like Thanksgiving, you can prepare this cake up to two months in advance and freeze it. Wrap the fully assembled, frosted cake (or even just the baked cake layers and curd separately) tightly in plastic wrap, then a layer of aluminum foil, and store it in an airtight container. When you’re ready to serve, simply transfer the cake from the freezer to the refrigerator a day beforehand, allowing it to slowly thaw overnight. On the day of serving, take it out of the fridge and let it come to room temperature for at least 2-3 hours. This gradual thawing ensures the cake retains its moisture, texture, and exquisite flavor, tasting just as fresh as the day it was baked.

Happy Baking, and a very Happy Thanksgiving to you all!

Recipe

Coconut Key Lime Pie Cake

Molly Murphy

Just like your typical key lime pie, but transformed into a stunning cake! Features moist coconut lime cake layers on a crunchy graham cracker crust, a luscious homemade lime curd filling, and a dreamy coconut buttercream frosting. This tropical delight is perfect for any celebration, including Thanksgiving, and can be made ahead of time.

Print Recipe
Pin Recipe

Ingredients

  

For the graham cracker crust

• 2 ¾ cups graham cracker crumbs
• ¾ cup unsalted butter melted
• ½ cup granulated sugar
• 1 teaspoon salt

For the Coconut Lime Cake

• 1 cup unsalted butter room temperature
• 1 ¾ cups granulated sugar
• ¼ cup vegetable oil
• 3 large whole eggs room temperature
• 3 large egg whites room temperature
• 3 cups all-purpose flour
• 1 Tablespoon baking powder
• 1 teaspoon salt
• 3 teaspoons lime zest
• 1 ¼ cups canned coconut milk low or no sugar, room temperature
• 1 Tablespoon coconut emulsion I use Lorann’s

For the Lime Curd

• 1 cup granulated sugar
• ½ cup lime juice
• 4 teaspoons lime zest
• 3 large eggs
• 3 large egg yolks
• 4 Tablespoons unsalted butter
• optional-green food gel tip: use a toothpick, a little goes a long way

For the Coconut Buttercream

• 2 cups unsalted butter slightly cold
• ¼ cup heavy whipping cream
• 7 cups powdered sugar measured and then sifted
• 1 Tablespoon coconut emulsion
• ¼ teaspoon salt
• If you want to have extra buttercream to pipe on the top I suggest making 1.5 of the recipe.

Instructions

 

For the graham cracker crust

• Preheat your oven to 375 degrees F. Spray three 8-inch round cake pans with non-stick cooking spray and line with parchment. Spray again. Set aside.
• In a medium sized bowl, combine the graham cracker crumbs, melted butter, salt and sugar. Stir until all the crumbs come together and you can squeeze the crumbs with your hand and they stick together.
• Divide the crumbs evenly between the three pans (a little over one cup in each pan). Press down firmly with the back of a measuring cup.
• Bake for 9 minutes and then let cool. While they are cooling, start prepping the coconut lime batter.

For the coconut lime cake

• Preheat the oven to 325 degrees F.
• In a medium sized bowl, whisk or sift together the all purpose flour, baking powder, lime zest and salt. Set aside.
• In the bowl of a stand mixer, fitted with the paddle attachment, beat the butter, oil, and sugar on high until fluffy and smooth, about 3 minutes. Scrape down the sides and beat again for 2 more minutes.
• Add the eggs and the egg whites, one at a time, and beat on medium speed until well incorporated. Then beat on medium high for 1 minute. Add the emulsion and mix on low, just until incorporated.
• With the mixer on the lowest speed, add ⅓ of the flour mixture to the liquid mixture followed by ½ of the coconut milk. Add another ⅓ of the flour mixture, and then the rest of the coconut milk, and finally add the remaining flour mixture. Don’t over mix. Only mix until just incorporated.
• With a kitchen scale, evenly distribute the batter to the prepped graham cracker crust pans (about 16 ounces of batter in each cake pan). If you don’t have a scale just eyeball it.
• Bake for 28-32 minutes, or until an inserted tooth pick has little to no crumbs sticking to it. Mine took the full 32 minutes, but it can go faster depending on your oven.
• After they are done baking, let the cakes cool for 10-15 minutes and than transfer them to a wire rack and let them cool until room temperature.
• Wrap in plastic wrap and store in fridge or freezer until ready to use.

For the Lime Curd

• In a medium size sauce pan, whisk the sugar, lime zest, and lime juice.
• In a small bowl, whisk the whole eggs, and egg yolks.
• On medium to high heat, and while whisking it in, slowly add the eggs to the lime/sugar mixture.
• Whisk constantly and let the mixture cook for about 7-8 minutes, depending on how hot your stove gets. Once it starts to bubble, I let it bubble for 3 minutes and then take it off!
• Remove from the heat and whisk in the butter. It might take a few minutes. I throw my butter in the mixture, let it sit for a couple of minutes and then whisk it after it melts. (If you are adding food coloring, this is the time to add it. Remember, a little goes a long way)
• Strain through a fine-mesh sieve into a glass or plastic Tupperware bowl. With a rubber spatula, make sure you push the lime mixture through the sieve.
• Press plastic wrap onto the mixture to help prevent a skin and let it sit out until it comes to room temperature, and then refrigerate at least 4 hours to set.

For the Coconut Buttercream

• In the bowl of a stand mixer fitted with a paddle attachment, beat the butter until creamed for about 2 minutes. This will help soften the butter.
• Turn the mixer off, and add the sifted powdered sugar, whipping cream, coconut emulsion and salt.
• Starting with the mixer on low, mix until everything is combined.
• Turn the mixer to medium-high speed and beat for an additional 3 to 5 minutes. The frosting will become lighter in color and texture. Scrape down the bottom of the bowl, and then beat again.
• To help remove the air bubbles, beat with a wooden spoon or a rubber spatula before spreading onto the cake.

Assembly

• Level the cakes if needed, place a small dollop of frosting on a cake board, and place one cake layer graham cracker side down in the middle of the cake board.
• With a piping bag, pipe a small ring around the edge of the cake.
• Place about ⅓ cup of the lime curd onto the cake. With the back of a spoon, gently push the curd to the edge of the piped buttercream
• Place another one of the cake layers graham cracker side down and repeating step two by adding a rim of buttercream, and then add ⅓ cup of the lime curd.
• Add the last layer of cake with graham cracker side down/
• Apply a thin layer (crumb coat) of the coconut buttercream around the cake, and freeze for 15 minutes.
• Apply the rest of the coconut buttercream and serve at room temperature.

Tried this recipe?Let us know how it was!