This Key Lime Cake layers tender, citrus-scented cake with a buttery graham cracker crust, tangy key lime curd, and sweet cream cheese frosting. Every bite tastes like summer sunshine. I first made this for my sister Lina's birthday last year, and she declared it better than any bakery cake she'd ever tried.
It's easier to put together than you'd think, and those graham cracker layers add such a fun crunch that reminds me of the Magic Cookie Bars Recipe we used to make as kids. If you love citrus desserts like Mini Margarita Cheesecakes or White Chocolate Peppermint Cheesecake, you're going to adore this one.
What Makes This Key Lime Cake Special
This isn't your average Key Lime Cake. It combines everything you love about key lime pie with the soft, celebratory feel of a layered cake. The graham cracker crust bakes right into the bottom of each layer, giving you that familiar pie texture without any extra work. Then comes the fluffy cake, packed with fresh lime zest and juice. Between the layers, smooth key lime curd adds a burst of tangy sweetness that makes each slice feel special.
The cream cheese frosting brings it all together with just the right balance of sweet and tart. It's rich without being heavy, and the lime flavor shines through beautifully.
Jump to:
Key Lime Cake Ingredients
Here's everything you need to make this beautiful Key Lime Cake with cream cheese frosting.
See Recipe Card Below This Post For ingtedient Quantites
Graham Cracker Crust
- Graham cracker crumbs: Forms the pie-style base for each cake layer and adds that familiar crunch.
- Salted butter: Binds the crumbs together and helps them bake into a firm crust.
- Granulated sugar: Sweetens the crust and helps it hold its shape.
Cake
- Cake flour: Creates a tender, soft crumb that's lighter than all-purpose flour.
- Granulated sugar: Sweetens the cake and helps it stay moist.
- Baking powder and baking soda: Work together to give the cake a nice rise and fluffy texture.
- Salt: Balances the sweetness and brings out the lime flavor.
- Salted butter: Adds richness and moisture to the batter. Room temperature butter mixes more smoothly.
- Vegetable oil or canola oil: Keeps the cake incredibly moist and tender for days.
- Eggs: Bind everything together and add structure.
- Buttermilk: Creates a soft, tender crumb with a subtle tang that complements the lime.
- Lime zest: Adds bright, aromatic citrus flavor throughout the cake.
- Key lime juice: Gives the cake its signature tart, tropical taste.
- Pure vanilla extract: Rounds out the flavors and adds warmth.
Key Lime Curd
- Granulated sugar: Sweetens the curd and helps it thicken properly.
- Key lime juice: Provides that intense, tangy lime flavor that makes this curd so special.
- Lime zest: Adds extra citrus aroma and depth.
- Egg yolks: Thicken the curd and give it a smooth, silky texture.
- Salted butter: Makes the curd rich and glossy.
Frosting
- Salted butter: Creates a creamy, smooth base for the frosting.
- Full-fat cream cheese: Adds tanginess and a slightly denser texture that holds up well for decorating.
- Powdered sugar: Sweetens and stabilizes the frosting.
- Key lime juice: Reinforces the lime flavor in every bite.
- Pure vanilla extract: Adds depth and sweetness.
- Lime zest: Gives the frosting extra citrus brightness.
- Fresh lime slices: Make a beautiful garnish that tells everyone what flavor to expect.
How to Make Key Lime Cake
Let's build this gorgeous cake layer by layer.
Preheat oven and prepare pans: Set your oven to 350°F and line three 8-inch round cake pans with parchment paper circles. Spray them well with baking spray or brush with cake release so the layers pop out easily later.
Make the graham cracker crust: Mix the graham cracker crumbs, sugar, and melted butter in a bowl until everything looks evenly moistened, like wet sand. Divide this mixture between your three prepared pans and press it down firmly with the bottom of a flat cup or measuring cup. Bake for about 8 minutes until the crust smells toasty and feels set, then take them out and let them cool while you make the cake batter.
Mix the dry ingredients: Whisk together the cake flour, sugar, baking powder, baking soda, and salt in a large bowl until everything's combined.
Add butter and oil: Using an electric mixer on low speed, drop in the softened butter one tablespoon at a time, mixing well after each addition. Keep going until the mixture looks sandy and crumbly. Pour in the oil and mix until it's evenly distributed throughout.
Add wet ingredients: Add the eggs, buttermilk, lime zest, key lime juice, and vanilla extract to the bowl. Mix everything together, stopping to scrape down the bottom and sides of the bowl so you get a smooth, evenly mixed batter with no dry pockets.
Fill cake pans and bake: Divide the batter evenly among your three pans, pouring it right over those graham cracker layers. Bake for 28 to 32 minutes, checking with a toothpick inserted into the center. It should come out clean or with just a few moist crumbs. Let the cakes cool completely in the pans before you even think about assembling.
Make the key lime curd: In a medium saucepan, whisk together the sugar, lime juice, lime zest, and egg yolks. Add the butter and set the pan over medium-low heat. Stir constantly (this is important, don't walk away) until the mixture thickens enough to coat the back of your spoon, usually 10 to 14 minutes. Pour the curd through a fine mesh strainer to catch any bits, then cover it with plastic wrap pressed right against the surface so it doesn't form a skin. Let it cool completely or pop it in the fridge.
Make the frosting: Beat the butter and cream cheese together with your mixer until smooth and creamy. Add the powdered sugar, key lime juice, vanilla extract, and lime zest. Mix until the frosting is light, fluffy, and spreadable.
Assemble the cake: If your cake layers domed on top, level them with a serrated knife. Place one layer on your cake plate or stand and spread a thin layer of frosting over it to seal the cake and keep the curd from soaking in. Use a piping bag to pipe a border of frosting around the top edge, creating a little dam. Spread half of the lime curd inside that border. Add the second cake layer and repeat with frosting, border, and the remaining curd.
Finish and decorate: Place the final cake layer on top and frost the entire cake with the remaining frosting, saving some for decorating. If you want, press some crushed graham cracker crumbs around the bottom third of the cake for texture and visual interest. Pipe swirls of frosting around the top edge and tuck fresh lime slices into the swirls. Pop the whole cake in the freezer for 20 minutes or the fridge for an hour to let everything set before slicing.
Substitutions and Swaps
You can adjust this Key Lime Cake based on what you have on hand.
If you don't have key lime juice, regular Persian limes work fine. The flavor will be slightly less tropical but still delicious and tangy. You'll need about 4 to 5 regular limes for the amount of juice in this recipe.
Don't have buttermilk? Make your own by adding 1 tablespoon of lemon juice or white vinegar to a measuring cup, then filling it to the 1 ⅓ cup mark with regular milk. Let it sit for 5 minutes before using.
For the graham cracker crust, you can use vanilla wafer crumbs or even crushed shortbread cookies instead. The flavor will change slightly, but it'll still taste wonderful.
If you prefer unsalted butter, go ahead and use it. Just add an extra pinch of salt to each component to balance the flavors.
Equipment For Key Lime Cake
Here's what you'll use to make this Key Lime Cake happen.
You'll need three 8-inch round cake pans. If you only have two, you can bake the third layer separately after the first batch is done.
An electric mixer makes the frosting smooth and fluffy, though you can do it by hand if you've got the arm strength.
A piping bag with a large open tip helps you create those pretty borders to hold the curd and makes decorating the top easier.
For the curd, use a medium saucepan and keep a whisk handy for constant stirring.
A fine mesh strainer ensures your curd is silky smooth without any cooked egg bits.
Storage Tips
This Key Lime Cake keeps beautifully, which makes it great for making ahead.
Store leftover cake in an airtight container in the refrigerator for up to 5 days. The flavors actually get better as it sits because the lime has time to meld with the frosting and cake.
You can freeze unfrosted cake layers wrapped tightly in plastic wrap and then foil for up to 3 months. Thaw them in the fridge overnight before assembling.
The key lime curd can be made up to a week ahead and stored in an airtight container in the refrigerator.
Frosted key lime cake slices also freeze well. Wrap individual slices in plastic wrap and freeze for up to 2 months. Thaw in the fridge for a few hours before serving.
Let the cake sit at room temperature for about 15 minutes before serving so the frosting softens slightly.
Expert Tips
- Make sure all your dairy ingredients are at room temperature before you start. This helps the batter mix more smoothly and gives you a more even key lime cake texture.
- Don't skip pressing the graham cracker crust down firmly. If it's too loose, it'll crumble when you cut the cake instead of staying in nice layers.
- When making the curd, keep the heat at medium-low and stir constantly. If it gets too hot too fast, the eggs can scramble.
- Freeze the assembled key lime cake for 20 minutes before frosting the outside. This firms up the layers and makes the whole thing much easier to work with.
- Use a hot, dry knife to cut clean slices. Wipe the knife between cuts for the prettiest presentation.
Why You'll Love This Key Lime Cake
This key lime pie cake hits all the right notes. It's bright and citrusy without being too tart, and those layers of curd and frosting make every bite feel indulgent. The graham cracker crust adds texture and that nostalgic pie flavor we all love.
It looks impressive, but it's actually pretty straightforward to make. You don't need any fancy techniques, just a bit of time and patience while the layers cool. The curd does need to thicken on the stove, but it's not tricky, just a little stirring.
This homemade key lime cake is perfect for birthdays, summer gatherings, or any time you want to serve something that feels special. Plus, it feeds a crowd, so you'll have plenty to share.
FAQ
What is Oprah's favorite Key lime cake?
Oprah has mentioned loving key lime cake from specific bakeries, though her exact favorite changes over time. What makes any key lime cake special is the balance of tart citrus with sweet frosting and a good crust. This recipe captures all those elements, and honestly, once you try it, you might declare it your own favorite.
What is the difference between lime and Key lime?
Key limes are smaller, rounder, and more yellow than regular Persian limes. They have a stronger, more aromatic flavor that's both tart and slightly floral. Regular limes work perfectly fine in this recipe if you can't find Key limes, though the flavor will be a bit less intense. I've made this key lime cake both ways and loved it either time.
Why do they call it a Key lime?
Key limes get their name from the Florida Keys, where they were first grown commercially in the United States. They're originally from Southeast Asia but became popular in Florida because they thrive in that climate. The famous Key lime pie was invented in the Keys using these local limes, and the name stuck for anything made with them.
What is the flavor of Key lime cake?
Key lime flavor is bright, tart, and citrusy with a slightly floral, tropical note that regular limes don't quite have. It's more aromatic and complex, which is why people seek it out for special desserts. In this Key Lime Cake, the lime flavor comes through in every layer without being overwhelmingly sour, thanks to the sweet cream cheese frosting balancing everything out.
Related
Looking for other recipes like this? Try these:
Pairing
These are my favorite dishes to serve with Key Lime Cake
Key Lime Cake
Ingredients
- Graham cracker crumbs Approximately 20 full sheets of graham crackers for crust
- Salted butter Melted for graham cracker crust and frosting
- Granulated sugar For both cake and crust
- Cake flour For a soft and tender cake
- Baking powder Leavening agent for the cake
- Baking soda Aiding in cake rise
- Salt Enhances flavor balance
- Vegetable oil Or canola oil for moisture
- Large eggs Room temperature for structure and richness
- Buttermilk Room temperature adds moisture and tang
- Lime zest Freshly grated for intense lime flavor
- Key lime juice Freshly squeezed for tartness
- Vanilla extract For depth of flavor
- Granulated sugar For the lime curd
- Egg yolks For richness in curd
- Unsalted butter For thickening and richness in curd
- Full-fat cream cheese Room temperature for frosting texture
- Powdered sugar For smooth frosting consistency
- Fresh lime slices For garnish
Instructions
- Preheat the oven to 350°F. Line three 8-inch cake pans with parchment paper and spray with baking spray or brush with cake release.
- Mix together graham cracker crumbs, sugar, and melted butter until the mixture is evenly moist. Press the mixture evenly into the bottom of the cake pans to form a crust. Bake for 8 minutes and then set aside to cool.
- In a large mixing bowl, whisk together the cake flour, sugar, baking powder, baking soda, and salt.
- Add softened butter one tablespoon at a time to the dry ingredients, mixing well each time until the mixture forms coarse crumbs.
- Pour in the oil and continue mixing on low speed until the flour mixture is well-moistened. Add eggs, buttermilk, lime zest, lime juice, and vanilla extract. Mix until smooth, scraping the sides of the bowl as needed.
- Divide the batter evenly between the cake pans, pouring it over the prepared graham cracker layer.
- Bake for 28 to 32 minutes, or until a toothpick inserted into the center of each cake layer comes out clean with a few crumbs. Let the cakes cool completely before assembling. These can be made ahead and frozen for up to 2 months.
- In a saucepan, whisk together sugar, lime juice, lime zest, and egg yolks. Stir in butter and cook over medium-low heat, stirring constantly, until the mixture thickens enough to coat the back of a spoon (10-14 minutes). Strain the curd through a fine mesh sieve, then cover with plastic wrap. Cool completely or chill.
- To make the frosting, beat together the butter and cream cheese until smooth. Add powdered sugar, lime juice, vanilla, and lime zest. Mix until smooth and fluffy, but be careful not to overmix.
- Assemble the cake by leveling the layers if needed. Place one layer on a cake plate and spread a thin layer of frosting to prevent curd from soaking into the cake. Pipe a border of frosting around the edge to create a barrier for the lime curd. Spread half of the curd over the cake. Repeat with the second layer and remaining frosting and curd.
- Top the cake with the final layer and frost the top, leaving enough frosting to pipe decorative swirls. Press extra graham cracker crumbs into the frosting about ⅓ of the way up the sides. Pipe swirls around the top and garnish with fresh lime slices. Freeze for 20 minutes or refrigerate for 1 hour before serving.
Leave a Reply