Easy cake mix Key Lime Whoopie Pies are filled with a delicious macadamia nut buttercream for a whoopie pie you won’t forget! These Key Lime Whoopie Pies with Macadamia Nut Buttercream are what summer dreams are made of, and you’ll ADORE them!
I. LOVE. THESE. These Key Lime Whoopie Pies with Macadamia Nut Buttercream ruined my “I’m going to eat ultra-healthy this week” plan, and I don’t regret it. Not yet, anyway. Ask me next week. Though my answer will still probably no. They are SO WORTH IT.
These whoopie pies warrant all the cap letters. I’m not shouting, it’s just exuberance. These Key Lime Whoopie Pies with Macadamia Nut Buttercream totally deserve all the caps.
My secondary excitement is because I did a Google search and didn’t really see any other Macadamia Nut Buttercream frostings out there in the internet world. That’s significant because anytime I get an idea that I hope is novel and new, it’s been done before. Like, a lot. I’m happy that not only was the idea for Macadamia Nut Buttercream new and original, but it also actually worked.
It’s one thing to come up with the idea, and another thing altogether to actually get it to turn out. This recipe was a win-win!
The cookies… well, they’re just cake mix cookies actually, so nothing new here. I did doctor them up with key lime zest, and that makes a world of difference. Cake mix cookies are fantastic – some of my personal favorites. These Easter Chicks Lemon Cookies are another prime example! The key lime-flavored cake mix gets the key lime party started, and the zest amps up the lime flavor and adds freshness. They’re terrific. Soft and chewy and wonderful.
The macadamia nut buttercream is the true star of the show though. I basically made homemade macadamia nut butter by food processing the heck out of some roasted salted macadamia nuts. Then I used my Peanut Butter Frosting recipe, substituting macadamia nut butter instead. It worked perfectly. I was concerned that macadamia nuts wouldn’t have a strong enough flavor to carry the frosting, but they absolutely do. I was also worried that the frosting would be heavy and thick, and might not whip up into fluffiness. It does. Light and fluffy, perfectly flavored macadamia nut buttercream. I can’t get over my love for it.
Slathered between two soft and thick key lime cookies? I hardly know how it could get better than that. These Key Lime Whoopie Pies with Macadamia Nut Buttercream were amazing, and dare I say, one of my top favorite recipes on the blog!
If you love other cake mix cookies and super simple cookie recipes, check out these Easter Chicks Lemon Cookies or Easter Chick Cookies. Or these Grinch Cookies (Pistachio Pudding Cookies)!
Key Lime Whoopie Pies with Macadamia Nut Buttercream
Ingredients
- 1 key lime flavored cake mix
- 2 eggs
- 1/2 c. shortening
- zest of 2 limes
- 2 c. macadamia nuts
- 2 tbsp. coconut oil
- 10 tbsp. unsalted butter softened
- 2 1/2 - 3 c. powdered sugar
- 3-4 drops coconut extract
Instructions
- In a large mixing bowl, combine key lime cake mix, eggs, shortening, and lime zest.
- Roll into 1-inch balls, and place on ungreased baking sheets.
- Slightly flatten each dough ball.
- Bake at 350 degrees for 8-10 minutes, or until edges are lightly golden.
- Remove to a wire rack to cool completely.
- Meanwhile, to prepare buttercream, pulse macadamia nuts and coconut oil in a food processor until smooth. You are basically creating homemade nut butter. Process it until it's as smooth as you can get it!
- Transfer the macadamia nut butter to a large mixing bowl.
- Add the unsalted butter, and beat to combine.
- Add enough powdered sugar to create a frosting that is thick, but spreadable, between 2.5-3 cups.
- Add in coconut extract.
- Beat until light and fluffy, about 3-4 minutes.
- Pipe or spread frosting between two cookies. Enjoy!!
It’s not just me. I took these to dinner at my in-laws, and they were very well-received! 🙂 These Key Lime Whoopie Pies with Macadamia Nut Buttercream are a home run.
That macadamia nut buttercream is so unique and sounds delicious! Loving the color of these whoopie pies 🙂
That frosting is one of my favorite things in the world, ever! Thanks, Medha!
they do look wonderful Sarah! and macadamia nut buttercream is so unique!
Thank you so much!
Love your recipes. Just did find you.
So happy to have you here!! I hope you’ll try something and let me know how it turns out for you!
THESE ARE UNBELIEVABLE!!! I had key lime cookie mix so used that. Yes, the buttercream is the most wonderful thing in the world. I will buy that cookie mix whenever I see it to save for this. Wow, Sarah! What a fabulous recipe!
Had I known about the key lime cake mix, I might’ve used it too, though I am a big fan of cake mix cookies. The buttercream is LIFE! Isn’t it? So glad you liked them!!!
It’s difficult to compare the original peanut butter buttercream to the macadamia version. How much nut butter does 2 cups of macadamias make? Is it 1 cup? 1 1/2 cups? Because the peanut butter is 1 cup pb, 1 cup butter, 4 cups sugar. Macadamia is ? cup mb, 3/4 cup fats, 2 1/2 – 3 cups sugar. I have 3/4 macadamia butter I made a few days ago for this recipe, I don’t remember how much that was in whole nuts, so I’m trying to just go by ratios, but the two recipes are different. Not knowing how much macadamia butter that is is really throwing me, I think. Maybe I’m confusing myself. Help??? Please?????
You know what, don’t stress too much. I find that most buttercreams seem to have a mind of their own, and turn out a little different with ratios each time. You have 3/4 cup macadamia butter, correct? I would use that amount of macadamia butter, 1/2 cup butter, and then try adding about 2 cups powdered sugar to start… just add more powdered sugar as needed. I’m sure it will need more than 2 cups, but start on the low end, and go from there, adding a 1/4 cup more at a time. If it starts to feel too heavy and sugary, add a tablespoon or two of cream. Frostings aren’t always an exact science, so start with roughly equal amount of fats, and 2 cups powdered sugar, and then go from there! It will turn out great, I’m sure! Good luck!!!
Thank you so much! I made a cake with caramel filling and macadamia buttercream and it was a big hit. Thanks for replying so quickly. 🙂 🙂 🙂
Oh, wow, that sounds AMAZING. What a great idea – I need to make this buttercream again soon, and share it on a cake too. I love that idea! I hope you had a wonderful holiday!
We did, thank you! I think it’s going to be my holiday cake from now on. I’m so glad you had the idea for this buttercream. I’m going to use the peanut butter one too at some point, for a peanut butter cup themed cake.
This looks so good! Do you use the buttercream in any other recipes?
I don’t think there is a key lime cake mix, where did you find it? It’s not even on the internet.
Thanks for sharing! Do they keep long?
Where in the world do I find key lime cake or cookie mix? I have scoured all of my local stores AND amazon… am I missing something? Any suggestions for an alternative…? Dying to make these babies. Thanks so much!!
Whaaaaat. Omgosh, really? Even a lime cake mix will work, doesn’t have to be “key” lime! Ugh, I’m sorry you’re having trouble locating. I do think it can be a seasonal item, but I generally have good luck at Super Walmarts. I’m sorry that you couldn’t find it! If you pick up a lemon cake mix, which are universally easy to find, you could add lime zest and get a very similar result!