With a velvety key lime cake base and a tart key lime buttercream, each bite of these Key Lime Cupcakes will make you pucker with delight!
Desserts are welcome around these parts year-round. The only thing that changes are the kinds of desserts. During summer, I like to make desserts that are light and refreshing, rather than overly decadent.
These key lime cupcakes are exactly the type of dessert I welcome during the summer. With a velvety key lime cake base and a tart key lime buttercream frosting that will make you pucker ever so slightly, they make a delightful treat at the end of a summer BBQ or as a snack for backyard camp outs.
How to Make Key Lime Cupcakes with Key Lime Buttercream
The key lime cake gets its flavor from infusing milk with key lime zest, a technique I learned from The Sprinkles Baking Book and also applied in my Tangerine and Cranberry Muffins and Orange Cranberry Cake.
The cake recipe itself uses the reverse creaming method, rather than the traditional creaming method.
The traditional creaming method beats together butter and sugar, creating lots of air pockets. Eggs are then added, followed by flour. Gluten, the protein in flour that gives cakes their structure, begins forming as soon as it is added. During the baking period, those air pockets will expand to create a light and airy cake.
With the reverse creamaing method, butter is added to the flour mixture first in order to coat the flour with fat before adding any liquid. With a layer of fat as a barrier, gluten isn’t activated as quickly, resulting in a soft and velvety cake.
The reverse creaming method takes care of the texture and the infused milk takes care of the flavor. Together, they make for the ultimate key lime cake base.
The cupcakes are topped with a key lime buttercream, which uses fresh key lime juice and was adapted from my strawberry buttercream.
When I originally tested these cupcakes, I used lemon meringue frosting, but ultimately decided to splurge on buttercream. Feel free to use either!
Key Limes vs. Persian Limes
Many people cringe at the thought of having to cook/bake with key limes. They’re small, are full of seeds, and their juice yield can be disappointing. Can’t you just use regular (Persian) limes? The short answer, yes!
Key limes get their name from their Florida Keys origin. In the 1920s, a hurricane destroyed most of the key lime groves and the farmers replaced them by growing Persian limes (the larger limes commonly seen in U.S. grocery stores) in their place. Today, key limes are actually sourced from Mexico.
As far as taste goes, key limes are much more acidic than the Persian variety and have a more floral aroma. All that being said, unless you’re a super taster, you might not even be able to taste the difference between the two.
So, if you have a hard time finding key limes at your local store or don’t even want to deal with them, go ahead and use the equivalent amount of Persian lime zest or juice to replace the key lime zest or juice the recipe calls for.
*DO NOT USE the equivalent amount of limes. Use the equivalent amount of zest or juice.*
I am a purist, so when making key lime cupcakes, I HAD to use key limes. If you’re the same way, follow the following pro-tip to make the key limes easier to juice: microwave them for 10 to 20 seconds, until slightly warmed. Then, roll each lime on the work surface using the palm of your hand to soften the flesh before cutting and juicing.
Key Lime Cupcakes
Ingredients
Key Lime Cupcakes
- 1/2 cup whole milk, room temperature
- 1 tablespoon freshly grated key lime zest, about 4 key limes
- 1 1/4 teaspoons pure vanilla extract
- 2 egg whites, room temperature
- 1 1/2 cups cake flour, sifted
- 3/4 cups sugar
- 2 teaspoons baking powder
- 1/4 teaspoon salt
- 3 tablespoons unsalted butter, room temperature
- 3 tablespoons vegetable shortening
Key Lime Buttercream
- 1 cup unsalted butter, room temperature
- 3 1/2 cups powdered sugar, sifted
- 4 tablespoons fresh key lime juice, about 15 to 18 key limes*
- 1/2 teaspoon pure vanilla extract
- 1/8 teaspoon salt
Instructions
Key Lime Cupcakes
- Preheat oven to 350°F and line a standard muffin pan with cupcake liners.
- In a microwave-safe bowl, stir together the milk and zest. Microwave until just warmed, about 30 seconds. Allow to cool to room temperature.
- In a small bowl, whisk together 1/8 cup of the milk mixture with the vanilla and egg whites. Set aside.
- In the bowl of a stand mixer fitted with the paddle attachement, mix together the flour, sugar, baking powder and salt on low speed until combined.
- Add the butter and shortening and mix on medium until combined, resembling a seedy consistency (see photo above). Slowly add the remaining 3/8 cup of milk and continue to beat until moistened.
- Reduce the speed to low and add the egg mixture in three additions, scraping down the sides of the bowl as necessary between each addition.
- Fill each well of the prepared muffin pan 2/3 full. Bake for 16 to 18 minutes, until a toothpick inserted into the center of the center cupcake comes out clean.
- Allow the cupcakes to cool in the pan on a cooling rack for 5 minutes. Transfer the cupcakes to a cooling rack to cool completely before frosting.
Key Lime Buttercream
- In the bowl of a stand mixer fitted with the paddle attachment, beat the butter on medium-high speed until pale and creamy.
- Reduce the speed to low and add the powdered sugar, 1/2 cup at a time. Scrape down the side and bottom of the bowl with a rubber spatula.
- Add the key lime juice to the mixture, followed by the vanilla and salt. Continue mixing on low until combined. Increase the speed to medium for 10 to 15 seconds, until whipped and fluffy.
- Frost cooled cupcakes using an offset spatula or a piping bag and your favorite tip**. Garnish with key lime zest.
Notes
Cupcakes adapted from The Sprinkles Baking Book and Sweetapolita.
Frosting adapted from The PKP Way.
Note: This page contains affiliate links that help make The PKP Way possible. Should you choose to purchase anything via those links, I will receive a small commission paid by Amazon, not you.
I’m a southern Florida girl and love anything that is key lime. I have a tree in my backyard and am always on the lookout for new recipes. This cupcake sounds fantastic and love the explanation for the reverse creaming. There is also a product in the store called Nellie & Joe’s Key Lime Juice which is pretty authentic if key limes can’t be found. Thanks for the inspiration.
These key lime cupcakes are so delicious! This recipe reminds me of the one my grandmother used to make. So. Darn. Yummy!!!
Ha! Key Limes and Meyer Lemons are the “cousins” of our typical grocery store varieties of lemons and limes!
I made these today. I had to make two batches because the first one only gave me enough for 12 cupcakes. As for the taste, I have to say amazing. I follow instructions until I got to decorating. For decorations I made candied key lime slices and sprinkled with lightly baked graham cracker crumbs! They look and taste like heaven! Wish I could post a picture :(
They sound beautiful and so gourmet :) I would love to see a picture. Feel free to tag me on IG @thepkpway
Does this Key Lime Buttercream pipe well? Thanks.
Yes! I used the same key lime buttercream recipe to pipe the swirls on the cupcakes in the photos above :)
Thank you.
Recipe says serving size is 1 cupcake. That can’t be right so could you tell me how many cupcakes this recipe makes? Thank you
Hi there! Serving size of 1 pertains to the nutritional information. The recipe yields 10 cupcakes. Hope that helps!