Key Lime Marshmallow Buttercream is an exciting twist on the classic buttercream frosting that brightens up any dessert. With its fluffy texture and the delightful tang of key lime combined with the sweetness of marshmallow, this buttercream is a total crowd-pleaser. It’s perfect for frosting cakes, dipping cookies, or even straight from the bowl on a spoon (we won’t judge!). This frosting is not just delicious; it’s incredibly fun to make, creating a vibrant addition to your dessert tables.
I first stumbled upon the idea of combining key lime with marshmallow when trying to add a summery flavor to my favorite vanilla cupcakes. The moment I tasted this creamy delight, I knew I had struck gold! The zestiness from the key lime paired with the fluffy sweetness of marshmallow creates a mouthwatering experience that’s irresistible. If you’re looking to elevate your desserts effortlessly, this Key Lime Marshmallow Buttercream is just the recipe you need. I can’t wait for you to give it a try!
Why You’ll Love This Recipe
- Simple & Quick: Ready in just 20 minutes! Perfect for those last-minute baking adventures.
- Irresistible Flavor: A delightful blend of tangy key lime and sweet, fluffy marshmallow for an unforgettable taste.
- Eye-Catching Appeal: Its bright color and fluffy texture are sure to impress at any gathering.
- Flexible Serving: Great for cakes, cupcakes, cookies, or even as a dip for fruit — any time is the perfect time for this frosting.
- Diet-Friendly Options: Easily tweak it to make it dairy-free by substituting with vegan butter and cream cheese.
Ingredients You’ll Need
- ½ cup (1 stick / 113 g) unsalted butter, room temperature: This forms the creamy base of your buttercream. Make sure it’s softened for easy mixing!
- 1 jar (7 ounces) marshmallow creme (marshmallow fluff): Adds that signature sweetness and lightness. Avoid substitutes for the best texture.
- 4 ounces cream cheese, room temperature: Provides a nice tang that balances the sweetness of the frosting.
- 4 cups (500 g) confectioners’ sugar: Essential for that perfect frosting consistency. Use sifted sugar for a smoother finish!
- 1 to 2 tablespoons key lime juice: Freshly squeezed is best for that bright, zesty flavor. Adjust based on your taste preference.
- 1 teaspoon key lime zest: Enhances the lime flavor and adds a lovely speckled look.
- 1 pinch kosher salt: Just a tiny bit to balance the sweetness and enhance freshness.
- ½ teaspoon vanilla extract: A touch of vanilla rounds out the flavors beautifully.
How to Make Key Lime Marshmallow Buttercream
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Cream the Butter and Cream Cheese: In the bowl of a stand mixer fitted with the paddle attachment, beat the ½ cup (1 stick) unsalted butter and 4 ounces of cream cheese until smooth and creamy, about 2 minutes. You want them to marry perfectly for a fluffy texture.
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Incorporate the Marshmallow: Add in the 1 jar (7 ounces) of marshmallow creme, mixing until fully incorporated. Take your time to scrape down the sides of the bowl as needed, ensuring everything is well-mixed.
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Mix in the Sugar: With the mixer on low speed, gradually add in the 4 cups (500 g) of confectioners’ sugar, mixing until smooth and combined. Keep an eye on it, as this can get a bit messy!
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Add Key Lime Flavorings: Now, add 1 tablespoon of key lime juice, the 1 teaspoon of lime zest, a pinch of kosher salt, and the ½ teaspoon of vanilla extract. Mix until everything is fully incorporated. You’ll notice a beautiful aroma wafting through the kitchen!
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Adjust the Zest: Taste your frosting and add the second tablespoon of key lime juice if desired. This customization is part of the fun! You’ll want that perfect balance between sweet and citrus.
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Whip Until Fluffy: Increase your mixer speed to medium-high and beat for 1 to 2 minutes. The frosting should be light and fluffy and practically begging to be slathered on your desserts.
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Use Immediately: Your Key Lime Marshmallow Buttercream is ready for action! Frost cakes, cupcakes, cookies, or bars with glee!
Storing & Reheating
If you’re lucky enough to have leftovers, store your Key Lime Marshmallow Buttercream at room temperature for up to 2 days in an airtight container. If you need to keep it longer, pop it in the fridge, where it will be good for about a week. For long-term storage, you can freeze it in a freezer-safe container for up to 3 months. When you’re ready to use it, just let it thaw in the refrigerator overnight, and then give it a quick beat in the mixer to regain its fluffy texture.
Chef’s Helpful Tips
- Avoid Overmixing: Once you’ve added the confectioners’ sugar, don’t overmix, or you risk losing that lovely airy texture!
- Use Room Temperature Ingredients: Make sure your butter and cream cheese are at room temperature; this helps them blend smoothly.
- Check for Texture: If your frosting seems too thick, gradually add a bit more key lime juice until you achieve your desired consistency.
- Flavor Sample: Always taste as you go to make sure you love the lime brightness. Every lime can vary in flavor intensity!
- Make-ahead Option: This buttercream keeps well in the fridge, making it an excellent make-ahead option for parties.
Key Lime Marshmallow Buttercream is not just a recipe; it’s an invitation to enjoy flavors that celebrate brightness and joy. Imagine a lovely afternoon, with a slice of cake adorned with this incredibly fluffy frosting. As you take that first bite, the sweet tang of lime dances on your palate, bringing sunshine into your day. I encourage you to mix, taste, and revel in the process of making this delightful treat. Share it with family or friends, and you’ll create moments that are as sweet as the frosting itself. Enjoy!
Recipe FAQs
Can I use regular lime juice instead of key lime juice?
Absolutely! While key lime juice gives a unique flavor profile, regular lime juice works perfectly fine in this recipe. Just note that it may slightly alter the taste.
How do I soften my butter quickly?
Place your cold unsalted butter wrapped in a microwave-safe dish, and microwave it for just 5–10 seconds. Check and repeat if necessary until it’s softened but not melted.
What desserts pair well with Key Lime Marshmallow Buttercream?
This frosting works wonderfully with vanilla cupcakes, lemon cakes, and even chocolate desserts. It adds a lovely contrast to richer flavors!
How can I make this recipe vegan?
For a dairy-free take, substitute the unsalted butter with vegan butter and the cream cheese with a vegan cream cheese product. You’ll still get all that delightful flavor!
Print
Key Lime Marshmallow Buttercream
Key Lime Marshmallow Buttercream is a delightfully zesty and creamy frosting that brings a burst of citrus flavor to your cakes and cupcakes. Made with simple ingredients like marshmallow fluff and key lime juice, this easy-to-make buttercream is perfect for any occasion, ensuring every bite is delicious and memorable.
- Total Time: 20 minutes
- Yield: 3 cups 1x
Ingredients
- ½ cup (1 stick / 113 g) unsalted butter, room temperature
- 1 jar (7 ounces) marshmallow creme (marshmallow fluff)
- 4 ounces cream cheese, room temperature
- 4 cups (500 g) confectioners' sugar
- 1 to 2 tablespoons key lime juice
- 1 teaspoon key lime zest
- 1 pinch kosher salt
- ½ teaspoon vanilla extract
Instructions
- In a stand mixer bowl fitted with the paddle attachment, combine the butter and cream cheese. Beat on medium speed until smooth and creamy, around 2 minutes.
- Add the marshmallow creme and mix thoroughly, making sure to scrape the bowl sides as needed.
- With the mixer on low, gradually incorporate the confectioners’ sugar until the mixture is smooth and well mixed.
- Stir in 1 tablespoon of key lime juice, key lime zest, kosher salt, and vanilla extract until everything is well combined.
- Taste the frosting; if you prefer more citrus flavor, mix in the additional tablespoon of key lime juice to balance sweetness and acidity.
- Increase the mixer speed to medium-high and beat for 1 to 2 minutes until the frosting becomes light and fluffy.
- Spread the frosting immediately onto cakes, cupcakes, cookies, or bars.
Last Step:
Please leave a rating and comment letting us know how you liked this recipe! This helps our business to thrive and continue providing free, high-quality recipes for you.Notes
For optimal fluffiness, ensure your butter and cream cheese are at room temperature before mixing.
Store any leftover frosting in an airtight container in the refrigerator for up to 5 days.
If the frosting becomes too thick, add a splash of milk to reach the desired consistency.
- Prep Time: 10 minutes
- Cook Time: 10 minutes
- Category: Dessert
- Method: Mixing
- Cuisine: American
Nutrition
- Serving Size: 1 tablespoon
- Calories: 110
- Sugar: 17g
- Sodium: 10mg
- Fat: 4g
- Saturated Fat: 2.5g
- Unsaturated Fat: 1.5g
- Trans Fat: 0g
- Carbohydrates: 18g
- Fiber: 0g
- Protein: 1g
- Cholesterol: 20mg
