The Perfect Coconut Key Lime Pie Cake

Coconut Key Lime Pie Cake – Layers of coconut lime cake, coconut buttercream, key lime curd, toasted graham cracker, and toasted coconut.

Coconut Key Lime Pie Cake

Resharing my Coconut Key Lime Pie Cake as green is in the air with St. Patrick’s Day around the corner and this pop of green from the lime curd is just so fun!

The idea for this cake originally came from my stepdad. He is the biggest fan of key lime pie. For months and months he begged me to do a key lime cake, but I keep putting it at the bottom of my cake list because the flavor didn’t really speak to me (probably because it’s a pie flavor and pie isn’t really my cup of tea, as you know).

But as I started to think about this flavor, I realized the reason I was hesitating to make this particular cake was because I couldn’t figure out what I wanted in it.

I was later at Porcupine Grill in Salt Lake with my mom and stepdad, and per usual, Garry ordered the key lime pie for dessert. I took a bite to see if his love of the dessert had rubbed off on me at all. And while I didn’t suddenly love key lime pie, this bite did turn a light bulb on in my head!

The cake itself didn’t need to be lime flavored like I was originally stuck on. This cake just needed a lime element to it. Something with a real lime flavor like you get from the custard in the pie. It also occurred to me that I definitely needed a graham cracker crust. The one element of the pie I decided not to throw into the cake was the meringue topping. It’s too airy and flavorless for a cake, in my opinion.

So without the meringue element, I started to brainstorm other flavor combinations and quickly settled on coconut as the companion to the key lime. With coconut and graham cracker crust in the mix, I was ready to make this cake.

Graham Cracker Crust or Crumbs (Updated)

The graham cracker crust is the same one I use for my Ultimate S’mores Cake and bakes beautifully with the moist and tender coconut cream cake on top.

UPDATE: However, I know that it can be difficult to cut through the crust on the bottom of the cake, so I’ve updated the recipe to include the option of making graham cracker crumbs to use between cake layers instead. The option for the graham cracker crust is still there. I just wanted to make sure you had options.

Buttercream

I also did a coconut buttercream that I flavored with coconut emulsion for a soft, creamy coconut flavor. The tart key lime curd in between each layer provides a nice balance to all the sweetness in the buttercream and cake. I also decided to throw in some toasted coconut – simply because I love different textures in my cake.

Just take a look at all those scrumptious layers! (This is a look at the old version with the graham cracker crust).

After finishing the cake, I was excited to get my hands on the scraps and create a sample piece for myself. I’ll be honest, I was hoping to at least like it, but didn’t expect to love it… but you guys, I seriously died over this cake! I couldn’t stop eating it and literally danced around my kitchen I was so excited about this cake!

Assembly Tips

Stacking and Crumb Coat

Final Coat

The cake layers are moist, the curd is subtly tart, the buttercream is incredibly silky, and the graham cracker crust and toasted coconut are the perfect accents to this pie turned cake!

Enjoy!

Coconut Key Lime Pie Cake

5 from 23 votes

Layers of toasted graham cracker, coconut lime cake, coconut buttercream, key lime curd and toasted coconut.

Prep Time 1 hr

Cook Time 45 mins

Total Time 2 hrs 45 mins

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Ingredients

 

FOR THE LIME CURD

• 1 cup (200 g) granulated sugar
• 1/2 cup (120 g) fresh lime juice (about 4 large limes)
• 4 teaspoons (7.2 g) lime zest
• 3 whole eggs at room temperature
• 3 egg yolks at room temperature
• 2 teaspoons (8 g) LorAnn key lime flavor
• 4 tablespoons (56 g) unsalted butter, cold, cut into cubes
• Green food gel optional

FOR THE GRAHAM CRACKER CRUST/CRUMBLE (See instructions to make either option)

• 1 1/2 cups (180 g) graham cracker crumbs, about 12 rectangular crackers (this is best done in a food processor or blender, but can be done by placing the graham crackers in a zip-lock bag and rolling over the crackers with a rolling pin)
• 1/2 cup (113 g) unsalted butter, melted
• 1/4 cup (50 g) granulated sugar
• 1/4 (1.5 g) teaspoon salt

FOR THE COCONUT LIME CAKE

• 3 cups (345 g) cake flour
• 1 tablespoon (10 g) baking powder
• 1 teaspoon (5.6 g) salt
• 1 cup (226 g) unsalted butter, room temperature
• 1 1/2 cups (350 g) granulated sugar
• 8 large egg whites, room temperature
• 1 tablespoon (16 g) coconut emulsion
• 1 teaspoon (4.2 g) vanilla extract
• 2 teaspoons (11.2g) lime zest
• 1 cup (231 g) canned coconut milk, mix the cream and the liquid really well.

FOR THE BUTTERCREAM

• 2 cups (452 g) unsalted butter, slightly chilled
• 1/4 cup (60 g) cream of coconut
• 6 cups (750 g) powdered sugar, measured then sifted
• 4 teaspoons (16.8 g) coconut emulsion
• Pinch of salt
• *This buttercream recipe makes enough to fill and cover your cake. If you want to add additional piping you’ll want to make an extra ½ batch.

FOR THE COCONUT

• 1 1/2 cups (150 g) sweetened shredded coconut

Instructions

 

FOR THE CURD

• In a small sauce pan, combine the sugar, lime juice, and lime zest over medium heat. Stir until the sugar is dissolved. Add the key lime extract, egg yolks and whole eggs, stirring while you add them. Continue to stir while the mixture cooks for about 5 to 6 minutes. The mixture will thicken during this time. Remove it from the heat and add the butter. Stir until smooth.
• Run the curd through a fine mesh sieve. Once cooled, place plastic wrap directly on top of the curd and refrigerate for at least 4 hours.

FOR THE GRAHAM CRACKER CRUST

• Preheat your oven to 375 degrees F. Spray three 8-inch or four 6-inch round cake pans with non-stick spray and then line with parchment. Spray again. Set aside.
• In a medium sized bowl combine the graham cracker crumbs, melted butter and sugar. Stir until all the graham cracker crumbs are damped by the melted butter.
• Divide evenly between the three pans and press down firmly with your hand or the back of a spoon.
• Bake for 8-10 minutes, until golden brown. Let cool while you make the coconut lime cake.
• OR

FOR THE GRAHAM CRACKER CRUMBLE

• Preheat your oven to 375 degrees F. Line a baking sheet with parchment paper. Set aside.
• In a medium sized bowl combine the graham cracker crumbs, melted butter and sugar. Stir until all the graham cracker crumbs are damped by the melted butter.
• Evenly spread the crumbs on the baking sheet, leaving some larger chunks in the mix.
• Bake for 8-10 minutes, until golden brown. Let cool while you make the coconut lime cake.

FOR THE CAKE

• Preheat your oven to 325 degrees F.
• In the bowl of a stand mixer fitted with the paddle attachment, cream the butter and the sugar together on medium speed for two minutes.
• Gradually add the egg whites, making sure to scrape down the sides and the bottom of the bowl between additions. Mix on medium-high for 2 minutes after all the eggs are added.
• Add the coconut emulsion and vanilla extract.
• In a medium size mixing bowl, whisk the cake flour, baking powder, lime zest and salt.
• Turn the mixer on low speed and alternately add the flour mixture and the coconut cream, starting and ending with the flour mixture. Mix until combined.
• Evenly distribute the batter over the graham cracker layers (if making with a crust), or pour into prepared pans with no crust, in the three pans and level with an offset spatula.
• Bake for about 23-25 minutes, or until the tops are slightly golden brown and the edges of the cake start to pull away from the sides of the pan. Don’t turn off your oven.
• Let cool in pans for 10 minutes and then invert onto cooling racks to cool completely.

FOR THE COCONUT

• Line a baking sheet with parchment paper and evenly spread the shredded coconut across the pan in one layer.
• Toast the coconut in the oven for about 10 minutes, checking and stirring every 2 to 3 minutes, until the coconut is golden brown all over.
• Let cool completely before use.

FOR THE BUTTERCREAM

• In a stand mixer fitted with a paddle attachment, combine the butter and coconut cream. Beat on medium-high speed for 1 to 2 minutes, until light and fluffy.
• With the mixer on low speed, gradually add the sifted powdered sugar, followed by the extracts and salt.
• Turn the mixer to medium speed and beat the frosting until it is light and fluffy, about 2 to 3 minutes.
• Before frosting your cake, make sure to mix the frosting by hand with a wooden spoon to push out the air pockets. 

ASSEMBLY

• Level each cake layer with a knife or cake leveler.
• Place your first cake layer, right-side up, on a cake plate or cake board. Cover the cake layer with frosting, allowing some of the frosting to go over the edge of the cake, and then pipe a rim around the cake to act as a barrier to the lime curd.
• Pour and spread about 3 to 4 tablespoons of lime curd. Cover with toasted coconut (and the graham cracker crumbs IF YOU DID NOT bake the graham cracker on the bottom of the cake). 
• Repeat step 2 and 3 for the second layer, and then place the final cake layer on top, top side up as well. Frost the entire cake with a thin coat of frosting to lock in the crumbs. Freeze the crumb coat for 10 minutes. 
• After the crumb coat is chilled, continue frosting the cake and decorate with toasted coconut and lime zest. 

Cuisine Cake

Course Dessert

Keyword Coconut, Coconut Buttercream, Coconut Cake, Graham Cracker Crumble, Key Lime Pie, Lime Curd

Have you tried this recipe?

I’d love to see it! Follow @cakebycourtney on Instagram, take a photo and tag it with #cakebycourtney.