Why You’ll Love This Key Lime Cake
Cake layers: the cake layers are subtly infused with key lime flavor, but they still have a sweet vanilla cake taste, so the cake isn’t overpowered by tartness. Frosting: to achieve the most key lime flavor in the frosting, we’ll stir in a homemade lime curd. I first used this technique in my lemon frosting (this is a game changer for infusing flavor into frostings!). Decoration: a crown of stabilized whipped cream and miniskirt of graham cracker crumbs puts things over the top and gives everything an authentic key lime pie taste and feel. Technique: from the reverse creaming method used to make the tender cake layers to the curd-infused frosting, every bit of work you put into this cake will be well worth the reward.
A Few Things to Know
My current favorite cake, key lime cake isn’t just impressive to look at, it’s an absolute flavor masterpiece (if I do say so myself)! With subtly key lime flavored cake layers, a smooth and silky cream cheese key lime frosting, and generous dollops of whipped cream frosting (optional, but so recommended), it’s simultaneously decadent and totally refreshing for summer. A touch of graham cracker crumbs around the bottom adds a nice touch of sweetness and texture too! The end result is the perfect balance of sweet and tart. I went through many, many trials and variations developing this recipe and finally nailed the tender, soft, but slightly more dense crumb I was looking for in the cake layers. For the frosting, one that started with a cream cheese frosting base was the winner with my taste testers (and myself) every time.
Ingredients
Let’s chat about a few of the key ingredients in the cake itself, and then I’ll do the same for the frosting.
Key lime juice. Key limes, let alone good, juicy ones, can be difficult to find depending on your location and time of year. You can substitute “regular” lime zest for the key lime zest, but for the juice I really recommend using a key lime juice. If you can’t find actual key limes, most stores carry the juice. Look for a brand called “Nellie & Joe’s Key West Lime Juice”, as that one works very well here (I have made the cake using this juice multiple times). All-purpose flour. I found that regular all-purpose flour (plain flour in the UK) worked best here (rather than cake flour). Butter & oil. Like so many of my cake recipes, I am using a combination of oil and butter to create a moist, flavorful crumb in this key lime cake. Oil is also especially helpful for preserving moisture in cakes that need refrigerated, like this one. Vanilla. Even though we are flavoring the cake with lime juice and zest, a touch of vanilla is still appropriate here. It is subtle, but softens the tartness of the limes a bit.
Frosting Ingredients
Cream cheese. Just like when making key lime cheesecake, you must use full-fat, brick-style cream cheese for this key lime frosting. The spreadable kind sold in tubs (or the low-fat variety!) will be far too soft and you will have a runny frosting. Eggs. We’ll need just the yolks (so feel free to save the whites for coconut macaroons or meringues). This will form the base of our key lime curd, which we will beat into our frosting. Key Lime Juice. See my note above; I typically can’t find key limes when I want them, so I used bottled key lime juice (and while fresh will always be my preference, bottled works well here!). Graham cracker crumbs. These are optional, but for a key lime pie vibe, you can press some graham cracker crumbs up the sides after frosting. These add a nice texture too!
No vanilla here, as this would dampen the fresh lime flavor. SAM’S TIP: Unlike many citrus fruits that reach their peak during the winter, limes are in season during the spring and summer months. So you might want to consider saving recipes like orange cookies and lemon cake for the winter, and make key lime cake when the weather is warm! This is just an overview of the ingredients I used and why. For the full recipe please scroll down to the bottom of the post!
How to Make Key Lime Cake
Make the Cake Layers
Frosting
Yes, making a homemade key lime curd is more time consuming than simply adding a splash of juice into the frosting, but it really nailed the flavor I was looking for, whereas just adding lime juice simply does not do the trick. I promise, the extra work is well worth it!
Assembly
SAM’S TIP: Let the curd cool completely and add it gradually, or your frosting could break. This can be hard to fix (I talk a bit about this in my raspberry frosting post), so prevention is best. This key lime cake is the perfect summer birthday cake! I can’t wait to hear how you like it. Enjoy! And If you’re enjoying these fun and flavorful cakes, definitely check out my chocolate raspberry cake and new cannoli cake next! Let’s bake together! Subscribe to my newsletter to be notified of all the newest recipes, and find my free recipe tutorials on YouTube 💜
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