Happy Friday! Do you have any fun plans this weekend? We are relaxing this weekend--the in-laws were here last weekend, so we're going to take it easy. Although I'll be baking a lot to get ready for some fun posts while I'm in Ireland in two weeks! Whatever your plans are, you should make these cupcakes.

I have a side bakery business, and these are one of my most popular cupcakes. If you like key lime and tart flavors, you'll love these cupcakes. It's a vanilla cupcake, a key lime curd filling, and a cream cheese frosting. People rave about these. They take a little while to make because of all the components, but it's not too bad. I usually make the cupcakes and curd one day and then make the frosting, fill, and frost the next day. These are perfect for summer, and they would be a big hit at your next BBQ. 

The vanilla cupcake recipe is what I've created for high altitude, so if you're not at high altitude, don't use it. Use your favorite from scratch recipe or even a box mix. You'll make up for the box mix by making your own curd and cream cheese frosting (please don't buy that in the can--gross!). This recipe makes 12-14 but you can easily double it to make 24-28 cuppies.

Key Lime Cupcakes Recipe
Makes 12-14
Print this recipe

For the Cupcakes (high altitude):
1 1/2 cups cake flour
1 1/4 teaspoon baking powder
1/4 teaspoon salt
8 tablespoons butter
1 cup minus 3 tablespoons sugar
2 eggs plus 1 egg white
1 cup buttermilk
1/4 cup instant vanilla pudding mix

For the Key Lime Curd (any altitude):
1/4 cup key lime juice (about 10 key limes)
1/2 tablespoon key lime zest
1 egg
2 tablespoons + 2 teaspoons sugar
1/4 cup butter, softened and cut into two pieces

For the Cream Cheese Frosting (any altitude):
3/4 package cream cheese (6 ounces)
6 tablespoons butter
12 ounces powdered sugar (about 2 3/4 cups)
1/8 teaspoon salt
1 teaspoon vanilla

1 lime with rind removed, sliced, and twisted

To make the high-altitude cupcakes, preheat your oven to 375 degrees and place cupcake liners in your cupcake pan(s). Mix together the flour, baking powder, salt, and instant vanilla pudding mix and set aside. In a mixing bowl fitted with the paddle attachment, cream together your butter and sugar. Add the eggs one at a time until incorporated. Scrape down the sides of the bowl. With the mixer on low speed, add the flour mixture and buttermilk in two additions, starting and ending with the dry ingredients. Mix on low until incorporated, scrape down the sides of the bowl, and mix for another 10-15 seconds. Divide the batter into the prepared muffin liners. You want to fill each liner about 2/3 full.

Bake for 15-17 minutes or until a toothpick inserted into the middle comes out clean. Cool in the pans for 5-10 minutes and remove to a wire rack. Cool completely before filling and frosting.

If you're not a high altitude, use your favorite scratch vanilla cupcake recipe or box mix and cool completely before proceeding.

To make the key lime curd
, whisk together the key lime juice, zest, egg, and sugar in a mixing bowl set on top of a saucepan with simmering water (this is the double boiler method). Add butter and whisk until thickened and smooth (a thermometer would read 160-170 degrees). Strain through a fine mesh strainer into a clean bowl and cover with plastic wrap to chill. It will pipe into your cupcakes much easier if it's chilled.

To make the cream cheese frosting, in your mixing bowl fitted with the paddle, cream together the butter and cream cheese until smooth. Add the vanilla and salt and mix until incorporated. Add the powdered sugar one cup at a time and mix until smooth. It's best to weigh your powdered sugar because your amount in cups will depend on your humidity. If you don't have a kitchen scale, you'll want the frosting to be thick enough to pipe onto the cupcakes. Store leftover frosting in the fridge or freezer.

To assemble the cupcakes, use an apple corer or a knife to cut a hole in the center of your cupcakes. You don't need to go to the very bottom of the cupcake. Fill the hole with the chilled key lime filling. You can do this with a spoon, a pastry bag, or a sandwich bag with the corner snipped off. You don't need to place cake over the hole as the frosting will cover it. Pipe frosting on top of the cupcake. Garnish with lime twists or sprinkles.

Cupcakes adapted from Annie's Eats
Key Lime Curd adapted from Confections of a Foodie Bride
Cream Cheese Frosting from The Pioneer Woman Cookbook 
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06/01/2012 3:05am

Oh these are too pretty to eat! Your pictures are simply stunning.

06/01/2012 8:10am

These look amazing! And I *love* that you're so clear on the fact that the recipe is for high altitude (which is just what I need!).

Have *so* much fun in Ireland... My husband and I were there in 2006 and loved every minute of it.

06/01/2012 9:27am

Mmm. Anything involving citrus curd and cream cheese frosting makes me happy.

06/01/2012 10:04am

These are beautiful! I'm going to have to try making the key lime curd!

06/01/2012 10:27am

These look amazing! I rarely bake cupcakes, but I might have to make an exception for these.

06/01/2012 4:03pm


06/01/2012 7:57pm

These sound amazing!! I can imagine why these are so popular with your bakery clients.

Debra Kapellakis
06/05/2012 12:06am

So lovely and light and yummy.

06/05/2012 3:39pm

This looks like a great summer recipe! I absolutely love key lime, I know I would absolutely love these cupcakes!!!

06/06/2012 9:27am

are these cupcakes mini? =)

08/05/2012 5:02pm

I made this wonderful recipe today! Thank you so much for sharing it.
Will definitely be making these cupcakes again :D

08/23/2012 7:12pm

Thank you so much for this fab recipe! It is my family's favorite cupcake EVER and we have visited many a cupcake shops! Wish we could visit yours and try out some more of your delicious creations! (Made them a few days ago and am now on round 2!)

09/27/2012 9:24pm

When you say "1/4 key lime juice (about 10 key limes)" do you mean 1/4 cup of the juice for the curd?

She Makes and Bakes
09/27/2012 9:34pm

Whoops. It should be 1/4 cup key lime juice. Sorry about that!

10/21/2012 6:41pm

Very tasty best with zest in the icing as well


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