Cakes and Cupcakes/ Desserts and Sweets

Key Lime Cake From Scratch

Perfectly tart with the right amount of sweet, this key lime cake recipe holds a special place in our hearts (and stomachs!).

Key Lime Cake From Scratch - Delectably tart, perfect for serious key lime lovers. Includes recipe for white chocolate buttercream frosting. *

The top layer of our wedding cake was key lime cake. We had it recreated for our first year anniversary. While it’s made an appearance here and there for birthdays and other celebrations, we always always associate key lime cake with our wedding cake. Since our 10 year wedding anniversary is a few short days away, I couldn’t resist sharing the recipe on the blog. How else does one celebrate such a milestone without cake? In fact, by the time our anniversary rolls around, I’ll have posted recipes for all three tiers of our wedding cake. One is already on the blog… can you guess which? 

If you spend any amount of time reading the blog, you’ll realize that the Godfather and I really really love key limes. There are recipes for key lime cookies, tart, margaritas, cheesecake, macarons… even tacos! I think our Floridian roots are a little obvious haha. It only makes sense we had key lime cake at our wedding, doesn’t it?

Key Lime Cake From Scratch - Delectably tart, perfect for serious key lime lovers. Includes recipe for white chocolate buttercream frosting. *

What I really love about this recipe for key lime cake is that the flavor of the key lime is very pronounced. I like my key lime desserts to be on the slightly tart side, and this cake recipe tastes like a key lime pie with cake texture. Because the cake is on the tart side, I like to pair it with a sweeter frosting. I opted for a white chocolate butter cream, which is just a slight variation on your standard American buttercream, and provides the perfect compliment – in my opinion – to balance the cake. If you’d prefer to use something else, we’ve also liked cream cheese frosting, white chocolate ganache, and pretty much any vanilla or vanilla bean icing.

Key Lime Cake From Scratch - Delectably tart, perfect for serious key lime lovers. Includes recipe for white chocolate buttercream frosting. *

Key limes, in case you’re unfamiliar, are small limes grown in tropical climates – like the Florida Keys. It’s a bit higher in acidity than a “standard” lime and has more of a sweet tart flavor, which is why it’s so popular in dessert recipes. The only challenge to making key lime desserts is that juicing the limes can be serious work! I used to juice by hand until I came to my senses and bought a citrus squeezer. Set it over your measuring cup and then squeeze your limes. It’s much easier, trust me.

You should be able to find key limes in the produce section of your grocery store. It’s often sold in 2 pound bags. If you can’t find it, you may substitute normal limes, but the flavor won’t be quite as strong. It’s still a delicious summertime cake! I hope you enjoy the recipe!

Key Lime Cake From Scratch - Delectably tart, perfect for serious key lime lovers. Includes recipe for white chocolate buttercream frosting. *

Key Lime Cake From Scratch
Prep Time
20 mins
Cook Time
40 mins
Total Time
1 hr
Servings: 16 -24 servings
Author: Goodie Godmother
Key Lime Cake
  • 2 g sticks unsalted butter 240, softened
  • 2 cups granulated sugar 400 g
  • 4 large eggs
  • tbsp zest from 6 key limes about 3
  • 4 cups all purpose flour 480 g
  • 1 tsp baking soda
  • 2 tsp baking powder
  • 1 tsp salt
  • 1 cup key lime juice 237 mL
  • 1 cup sour cream 227 g
  • 2 tsp vanilla extract
White Chocolate Buttercream Frosting
  • 12 ounces white chocolate 340 g
  • 3 ounces heavy cream 85 g
  • 2 g sticks unsalted butter 240, softened
  • 5-6 cups powdered sugar 568 - 681 g, sifted
  • 1 tsp salt
  • 1 tsp vanilla extract
  1. Preheat your oven to 350 F. Butter and flour 2 8" cake pans or place liners in 2 dozen cupcake wells. Set aside.
  2. Cream the sugar, key lime zest, and butter together in the bowl of a stand mixer fitted with the paddle attachment (or with a hand mixer) until light and fluffy (about 1-2 minutes). Scrape the sides of the bowl.
  3. Add the eggs one at a time, scraping the bowl after each addition, then stir in the vanilla extract.
  4. In a separate bowl, sift together the flour, baking powder, baking soda, and salt.
  5. Add half the sour cream to the egg mixture, then stir in half the flour mixture, add the rest of the sour cream, add the rest of the flour, then finish with the key lime juice and stir until just combined. The batter might look a little curdled, that's fine.
  6. Evenly distribute the batter between the pans. This is important because this recipe makes enough batter to bake so the cake domes slightly over the 8" round (2" height). This is convenient because you can level right in the pan, but not so convenient if you have too much batter and it bakes over, spilling in your oven. Alternatively, you can use a 9" pan, or two 8x3" pans. If you are making cupcakes, fill the cups about ⅔ full.
  7. Bake 20-25 minutes for cupcakes, 40-45 minutes for cake.
  8. Remove from the oven and allow to set for 10 minutes before turning cakes onto a cooling rack to cool completely before frosting.

To Make the Frosting:
  1. In a double boiler or in the microwave, melt together the white chocolate and heavy cream until smooth.
  2. In a clean bowl with a hand mixer, or using the paddle attachment on your stand mixer, beat the butter until light and fluffy. Scrape the sides of the bowl.
  3. Add two cups of powdered sugar, beating and scraping the bowl after each addition. Then pour in your white chocolate ganache and stir until incorporated.
  4. Add the remaining three cups of powdered sugar, one at a time, then stir in the salt and vanilla extract.
  5. Mix the frosting on low speed for 5-6 minutes.
  6. If your frosting is too thick, add a little heavy cream to thin. If it's too thin, add additional powdered sugar.
  7. Use immediately, covering with a damp cloth as you work so the buttercream doesn't crust.


Key Lime Cake From Scratch - Delectably tart, perfect for serious key lime lovers. Includes recipe for white chocolate buttercream frosting. *


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  • Reply
    July 28, 2018 at 10:38 am

    This looks delightful, but we are a household of 2 with poor self control – do you think the cake recipe will still work if I cut it in half to make one 8” cake? Thanks!

    • Reply
      Mary (The Goodie Godmother)
      July 28, 2018 at 5:30 pm

      It definitely works when cut in half. I’ve done so before and baked as a 2 layer 6″ cake, but it will work as a 1 layer 8″ cake too.

  • Reply
    July 17, 2018 at 9:56 pm

    Do you know where to get key limes in Nov/Dec in northwest Florida? Thanks.

    • Reply
      Mary (The Goodie Godmother)
      July 20, 2018 at 4:47 pm

      I’ve usually found them at the grocery store. Publix and even places like Wal-Mart often have them in stock. If not, check the local international grocery store. When I couldn’t find them anywhere else, I almost always found them there.

  • Reply
    March 11, 2018 at 3:17 pm

    What were the other layers of your wedding cake? I am thinking of doing this flavor as one of the layers for my daughter’s wedding cake as her favorite pie iss key lime but am stuck for what the other ones should be. Thanks!

    • Reply
      Mary (The Goodie Godmother)
      March 12, 2018 at 5:27 pm

      How sweet! Our other layers were peanut butter with I think an Irish cream mousse filling and almond cake with either white chocolate or amaretto. I think it’s so beautiful that you are baking your daughter’s cake. <3

  • Reply
    Cheryl Rosner
    August 8, 2017 at 9:44 pm

    I couldn’t make out how much butter you use, it’s printed 2g sticks of butter 240. I really want to bake this but I want to use the right amount of butter. Thanks

    • Reply
      Mary (The Goodie Godmother)
      August 8, 2017 at 9:58 pm

      2 sticks (1/2 lb)… sorry about that! I recently changed recipe card plugins and am still working through glitches in the conversion. I’ll update tomorrow when I’m on the computer again. 🙂

  • Reply
    Caroline @ Love Cake Create
    July 15, 2017 at 7:57 am

    Ooh, this cake looks and sounds incredible! I’ve got such a thing for limes at the moment, thanks for sharing a great recipe.

  • Reply
    April 14, 2017 at 5:11 pm

    That looks amazing. I’m a huge fan of key lime pie, so I’m thinking I’m gonna have to try this one soon. Pinning right now!

  • Reply
    Meaghan | Cook. Craft. Love.
    April 14, 2017 at 11:30 am

    Key lime takes me to the beach every single time. I can’t decide if I want to make this cake or your pie or both!

  • Reply
    Kristina @ Love & Zest
    April 4, 2017 at 10:00 pm

    This looks really great and how beautifully smooth you made it!

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