These Key Lime Cupcakes are a vanilla lime cupcake base topped with key lime buttercream- the ultimate combination of sweet and tart. It's basically summer in a cupcake!
The summer months are coming to an end, but it's still blazing hot (and humid) where I live. So I'm not quiteeee ready to cozy up to some apple crisp or pumpkin pie just yet.
Key Lime Cupcakes seemed like the perfect thing to make to bring a little sunshine into my life, because who doesn't love cupcakes and citrus. These cupcakes are so perfectly balanced between tart and sweet. They are the perfect treat to make me feel like I'm on a mini-vacation.
Key Limes vs. Persian Limes
If you didn't know (like my boyfriend), key limes are actually different than the typical limes you find in the grocery store!
Persian limes- larger, tarter, and have green skin & juice. These are the limes you typically buy in a grocery store.
Key limes- smaller, sweeter, have more seeds, and their skin & juice is more yellow than persian limes. They look like little lemons!
Key Limes were first brought to America in, you guessed it, the Florida Keys. They are still grown there (as well as Texas and California), but most of our key lime production comes from Mexico.
Can I use persian limes instead of key limes?
The short answer is yes! Unless you are some magically amazing key lime taster, you would probably not tell the difference between using persian lime juice/zest and key lime juice/zest. Read more below on how I combat not being able to purchase fresh key limes!
What can I use for Key Lime Cupcakes?
Key limes can be hard to find in grocery stores at any time of the year, even during peak key lime season. I did not find any key limes at my grocery stores so I opted for using key lime juice that you can typically find at most grocery stores. I also used the lime zest from persian limes, and you can hardly tell the difference!
- Key lime juice- If you can't find actual key limes you can use key lime juice! Here is what I used which I found in my local grocery store - as well as another one you can order on amazon.
- Lime zest- As I said above, if you can't find actual key limes, using persian limes for zest is totally fine! Unless you're an expert taste tester, you won't be able to tell the difference.
Key Lime Cupcakes- Buttercream tips and tricks:
- Make sure your butter is soft enough when starting. Room temperature butter gives you a creamy buttercream. I like to take my butter out of the fridge about an hour before to soften. If the butter is greasy, that means it's too warm! Stick it back in the fridge for 5-10 minutes.
- You will need an electric mixer for this buttercream because it really needs to be whipped on high speed to give it that light and fluffy consistency.
- Don't skip the salt- buttercream can get sweet with all the powdered sugar, so a little bit of salt really balances out the sweetness!
- Over-mixing buttercream can give it a lot of air bubbles. If you find this happened, grab a wooden spoon and begin stirring the buttercream by hand. Mash the frosting up against the side of the bowl to “pop” the bubbles, about 1-2 minutes. This will require a bit of arm muscle!
Other fruity recipes to try:
Key Lime Cupcakes
- 1½ cup all-purpose flour
- 1¼ tsp baking powder
- ¼ tsp salt
- 1 cup granulated sugar
- 1 stick unsalted butter, room temperature
- 1 large egg + 1 egg yolk
- 1 tsp vanilla extract
- ½ cup whole milk, room temperature
- 1 tbsp lime zest
- 2 tbsp key lime juice
Key Lime Buttercream
- 2 sticks unsalted butter, room temperature
- 4½ cups powdered sugar
- 2½ tbsp key lime juice
- 2 tbsp heavy cream
- 2 tsp lime zest
- pinch of salt
Make the Cupcakes:
- Preheat your oven to 350° F. Prepare your muffin tin with cupcake liners.
- In a medium bowl, combine the flour, baking powder, and salt. Set aside.
- In a large bowl, beat the sugar and butter together until light and fluffy. Add in the egg + egg yolk and vanilla extract and mix until combined.
- Alternate between adding the dry ingredients and the milk to the butter mixture until everything is combined. Lastly, add in the lime juice and zest, and mix until combined.
- Divide the batter evenly between the prepared muffin tins, filling each about ⅔ full.
- Bake until a tester inserted in the middle of the cupcakes comes back with just a few crumbs, about 15 to 18 minutes. Cool in the pans for 5 minutes before removing to a cooling rack to cool completely.
Make the Buttercream:
- With a handheld or stand mixer fitted with a paddle or whisk attachment, beat the butter on medium speed until creamy – about 2 minutes.
- Add the powdered sugar, lime juice, heavy cream, lime zest, and salt. Turn your electric mixture on low until the sugar has combined together, then beat on high speed for 3 minutes until light and fluffy. Scrape down the sides of the bowl when necessary.
- If your icing seems too thick, add a tbsp of cream at a time until you reach the right consistency. If the icing is too thin, add a tbsp of powdered sugar at a time.
- Frost the cupcakes when they are completely cooled by using an offset spatula or piping bag (or ziploc bag) and a tip. Garnish with lime zest.
- Plain cupcakes can be made ahead 1 day in advance, covered, and stored at room temperature. Frost the day of serving. Unfrosted cupcakes can be stored in the freezer for up to 3 months.
- Frosting can also be made 1 day in advance, covered, and stored in the refrigerator until ready to use. It can also be stored in the freezer for up to 3 months.
- After freezing or refrigerating buttercream, thaw in the refrigerator, bring to room temperature then beat the frosting for a few seconds so it’s creamy again. You may need to add a little milk or heavy cream if it’s still too stiff.
- Store leftovers in the fridge for 4-5 days.