Key Lime Pie Cupcakes with Key Lime Buttercream
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If you love the bright, tangy flavor of key lime pie, these Key Lime Pie Cupcakes are about to become your new obsession. We’re talking a light, buttery cupcake base filled with a creamy key lime filling and topped with a smooth, citrusy key lime buttercream frosting. They’re the kind of dessert that disappears fast at parties, potlucks, and summer cookouts. And the best part? You can make them with a box cake mix and have them on the table in under an hour.
The Secret: Key Lime Filling Inside Every Cupcake
What sets these key lime cupcakes apart from a standard lime-frosted cupcake is the filling. A simple mixture of key lime juice and sweetened condensed milk gets piped directly into the center of each cupcake, so every single bite is packed with that signature tart-sweet flavor. It’s the same combination that makes key lime pie so irresistible, just in cupcake form.
Can I use a boxed cake mix for cupcakes?
Absolutely, and I’m a big fan of this shortcut. A butter golden cake mix works perfectly as the base here. To make your box mix taste more homemade, swap the water for whole milk. It gives the cupcakes a richer, more tender crumb. You can also stir in a couple of tablespoons of key lime juice for extra citrus flavor. If you add the juice, just reduce the milk by 2 tablespoons to keep the liquid ratio balanced.
If you’d rather bake from scratch, use my from-scratch orange cupcake recipe and substitute key lime juice for any liquid citrus called for. Skip any citrus extract and use all vanilla instead.
What kind of lime juice should you use?
This is where it matters. Nellie & Joe’s Famous Key West Lime Juice (look for it near the baking ingredients, not in the produce section) has a distinct flavor that’s more floral and aromatic than regular lime juice. It’s also a huge time-saver compared to squeezing dozens of tiny fresh key limes. If you can find a good bottled key lime juice, use it. It makes a real difference in the final flavor.
Key Lime Buttercream Frosting
The frosting on these cupcakes is rich, creamy, and loaded with key lime flavor from both the juice and fresh lime zest. It pipes beautifully and holds its shape, making these easy to dress up for any occasion. A little extra zest on top adds a pop of color and a burst of fresh citrus aroma.
Tips for the best key lime cupcakes
- Use softened butter for the frosting so it creams smoothly without lumps.
- Add powdered sugar gradually to control the consistency.
- Let the cupcakes cool completely before filling and frosting, otherwise the filling will run.
- Store finished cupcakes in a sealed container in the refrigerator and bring them to room temperature before serving for the best texture and flavor.
How To Fill Cupcakes With Key Lime Filling
The trick to getting that creamy key lime filling inside every cupcake without making a mess is the right tip. I use a Wilton #230 bismarck tip (also called a filling tip), and it’s a total game changer. It’s long and pointed, so it goes straight into the center of the cupcake without you having to core anything out.
Here’s how it works: load your key lime filling into a piping bag fitted with the #230 tip. Hold a cupcake in one hand and insert the tip straight down into the center. Slowly squeeze as you pull the tip up and out, and you’ll actually feel the cupcake puff slightly as it fills. That’s how you know it’s working! Repeat with all 24 cupcakes.
Pipe frosting onto cupcakes and garnish with any remaining lime zest, if desired. Store cupcakes in a sealed container in the refrigerator and set them out to come to room temperature before serving.
Yes! Bake and fill the cupcakes up to a day ahead and store them covered in the refrigerator. Add the frosting the day you plan to serve them for the best presentation.
Key limes are smaller and more aromatic than Persian limes, with a slightly more floral, tart flavor. Bottled key lime juice is a convenient substitute for fresh and gives you that true key lime pie flavor.
You can freeze the unfrosted cupcakes for up to 2 months. Thaw overnight in the refrigerator, then fill and frost before serving.
Yes. Because of the sweetened condensed milk filling and butter-based frosting, these cupcakes should be refrigerated. Let them sit at room temperature for 20 to 30 minutes before serving.
Whether you’re making these for a summer barbecue, a birthday, or just because you’re in a citrus mood, these key lime cupcakes always deliver. The combination of that creamy filling and tangy buttercream is hard to beat. If citrus desserts are your thing, don’t miss these other cupcake favorites!
More Delicious Cupcake Recipes
- Chocolate Fudge Cupcakes with Chocolate Chip Buttercream
- Orange Cupcakes with Orange Cream Cheese Frosting
- Mint Chocolate Cupcakes with Mint Buttercream Frosting
- Pumpkin Spice Cupcakes
- Lavender Earl Grey Tea Cupcakes
- Egg Nog Cupcakes
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Key Lime Pie Cupcakes
Ingredients
- 1 box Butter golden cake mix *baked into 24 cupcakes according to package directions *see notes
- For The Filling:
- 1 tsp fresh lime zest
- 1/2 cup key lime juice
- 14 oz can sweetened condensed milk
- For The Frosting:
- 16 tbsp butter (2 sticks) softened
- 5 cups confectioners' sugar sifted
- 2 tbsp vanilla extract
- 3 tbsp key lime juice
- 1 tsp fresh lime zest
- 3 tbsp half and half
Instructions
- Make boxed cake mix per package directions and bake into 24 cupcakes.
- While cupcakes are cooling, first make the filling.
- Whisk together 1/2 cup key lime juice and the sweetened condensed milk.
- Place filling mixture inside a piping bag with a Wilton #230 filling tip attached. While holding a cupcake in one hand, use the other hand to insert the cupcake filling tip in the middle of the cupcake. Slowly pull the tip up and out as you feel the cupcake start to expand. Repeat with remaining cupcakes.
- Next, make the frosting.
- In a mixing bowl, cream softened butter and 1 cup powdered sugar until blended. Add lime zest, vanilla, lime juice and half and half. Slowly add remaining sugar, one cup at a time, until frosting is creamy and smooth.
- Pipe frosting onto cupcakes and garnish with any remaining lime zest, if desired.
- Store cupcakes in a sealed container in the refrigerator and set out to come to room temperature before serving.
Notes
Nutrition
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