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Key Lime Sheet Cake

Key Lime Sheet Cake: The ultimate Summer dessert! Packed with a sweet yet subtle tang of key lime flavor. This cake feeds a crowd and is a family favorite!

I began making Key Lime pies with my dad when I was a kid. I feel in love with the sweet tartness of those little limes. I’m really picky about key lime flavor. Some key limes recipes are just too sweet. I need that tart bite for it to feel real! This recipe was born from my love of Key Lime and my grandma’s favorite Texas Sheet Cake. It’s super easy and is the perfect addition to any Summer gathering!

Ingredients

Sheet Cake Batter

  • Unsalted butter
  • Water
  • Key Lime Juice – Fresh is always best but Key Limes can be difficult to find, and they’re tiny so you need a bunch! Unlike most recipes that bill themselves as Key Lime they are typically just Lime recipes. The juice I’ve linked here has been a staple in our house for YEARS. I’ve been able to find it near the bottled juices in my local grocery store, Target, WalMart, etc.
  • Flour
  • Baking Soda
  • Salt
  • Sugar
  • Eggs
  • Sour Cream
  • Vanilla Extract – I typically use clear extract in this recipe to keep the color of the batter light, but if you only have dark extract, use it, just beware that your batter will darker.

Syrup

  • Key Lime Juice
  • Sugar

Cream Cheese Icing

  • Butter
  • Cream Cheese
  • Powdered Sugar
  • Vanilla Extract – see note above about clear vs dark extract
  • Key Lime Juice

How to make Key Lime Sheet Cake

Melting Butter: In a medium sauce pan, melt butter then add water and key lime juice. Bring to a quick boil, then remove from heat and allow to cool while making the batter.

Cake Batter: Combine flour, salt, baking soda, and sugar in a mixing bowl. Add sour cream, and eggs and mix until well combined. Next, slowly pour in melted butter mixture. Mix on low as batter will be very thin. Scrape down sides and bottom of the bowl several times during mixing. Pour batter into a prepared jelly roll pan.

Baking Cake: Bake at 350*F for 20 minutes.

Syrup: a few minutes before the cake is done. baking, combine key lime juice and sugar over medium heat and allow sugar to melt. Once cake is done baking, use a fork to poke hole over the top of the cake. Drizzle or brush on syrup over warm cake. Allow to cool before icing.

Cream Cheese Icing: Add softened butter and cream cheese to mixing bowl and beat on medium-high for about 90 seconds or until well combined. Next, turn down mixer to low and begin adding powdered sugar in batches allow to fully incorporate between additions. Next add, vanilla and key lime juice and gradually increase speed to medium high and allow to mix for an additional 90 seconds until no powdered sugar pieces remain.

Process Steps to make Key Lime Sheet Cake

Convert this recipe to a Coconut Key Lime Sheet Cake

It couldn’t be easier to convert this Key Lime Sheet cake into an even more tropical-y flavored Coconut Key Lime Sheet Cake. All you need to do is replace the standard milk measurement in this recipe with coconut milk and add two tablespoons of Cream of Coconut when the recipe calls for melting the butter. Continue with the recipe below, however, feel free to add shredded coconut to the top of the cake once it has been iced. I prefer toasted coconut.

How to toast coconut

There are a few ways to toast your coconut – in the oven, on the stove, and if you can believe it right in your microwave. For this recipe, I suggest using sweetened shredded coconut as opposed to unsweetened. Keep an eye on your coconut – sweetened tends to brown a little faster because of the sugar. However, either way, they can burn quickly if not watched.

Oven Method – This process will take 5-10 minutes

Preheat oven to 325*F. Spread 1-1.5 cups on a cookie sheet in a thin layer. Stir coconut every few minutes to ensure even toasting. I urge you to not walk away from the oven. They can go from toasted to burnt VERY quickly. Once done to your desired toastiness, allow to cool for several minutes before scattering over the top of the icing.

Stovetop Method

In a heavy bottomed skillet, add coconut and heat over medium-low heat. Stir constantly to help coconut toast evenly. Once your shredded coconut is toasty and golden brown, remove from heat and allow to cool before scattering over the top of the icing.

Microwave Method

This method will need to be done in batches. Place 1/2 cup of shredded coconut on a microwave safe plate. Microwave in 30 second increments and stir in-between. Continue to microwave 30 seconds at a time until coconut is thoroughly toasted. Repeat process 1/2 cup at a time.

What if I can’t find Key Lime Juice?

If you cannot find Key Lime Juice or prefer to use regular lime juice, you can do so. You will need to make the following alterations to the recipe.

Melted butter: Instead of 1/2 cup water and 1/2 cup Key Lime juice, replace with 1/3 lime juice and 2/3 cup water.

Syrup: make a 1:1 replacement swapping out the juice for lime juice

Cream Cheese Icing: Use 1-2 tablespoons of lime juice. Taste the icing after incorporating 1 tablespoon to determine if you desire another tablespoon.

I love transforming old family recipes and giving them new life, like this Pumpkin Caramel Dump Cake. Sheet cakes are a delicious past time in our family. This fresh take on a traditional sheet cake is a refreshing addition to any Summer get-togethers. Do yourself a favor and give this Key Lime Sheet Cake a try!

Don’t miss out on these Summer favorites: The Best Lemon Bars, Buffalo Chicken Dip and Blackberry Margaritas

Close-up shot of a piece of Key Lime Sheet Cake on a plate with a fork

Key Lime Sheet Cake

Yield: 20 pieces
Prep Time: 10 minutes
Cook Time: 20 minutes
Total Time: 30 minutes

Key Lime Sheet Cake: The ultimate Summer dessert! Packed with a sweet yet subtle tang of key lime flavor. This cake feeds a crowd and is a family favorite!

Ingredients

  • Key Lime Sheet Cake Batter:
  • 1 cup butter, softened
  • 1/2 cup water
  • 1/2 cup key lime juice
  • 2 cups flour
  • 1 tsp baking soda
  • 1 tsp salt
  • 2 cups sugar
  • 2 eggs beaten
  • 1/2 cup sour cream
  • 1 teaspoon vanilla extract
  • Key Lime Syrup:
  • 2 tablespoons key lime juice
  • 2 tablespoons sugar
  • Key Lime Cream Cheese Frosting:
  • 1/2 cup Butter (softened)
  • 8 ounce Cream Cheese (softened)
  • 4 - 4 1/2 cups Powdered Sugar
  • 1 teaspoon vanilla extract
  • 2 Tablespoon Key Lime Juice

Instructions

  1. Preheat oven to 350* and prepare a 13x18 jelly roll pan with Bakers Joy (or another baking spray with a flour base)
  2. In a medium saucepan over medium heat, melt butter
  3. Add water and key lime juice to butter and bring to a boil
  4. Once boiling, remove butter mixture and allow to cool
  5. Next, combine flour, salt, and baking soda in a mixing bowl and whisk together
  6. Then, add sugar and combine
  7. Incorporate sour cream and one egg at a time - beating between each addition
  8. Add vanilla and slowly incorporate butter mixture
  9. Scrape down the sides and bottom of mixing bowl several times to ensure all ingredients are thoroughly combined
  10. Pour batter into prepared jelly roll pan and bake for 20 minutes or until a toothpick comes out of the center of the cake clean
  11. Next, in a small sauce pan, add key lime juice and sugar and cook until all sugar is dissolved
  12. Once out of the oven, quickly poke holes over the cake using a fork
  13. Pour or brush sugar mixture over the cake and allow to cool
  14. In a clean mixing bowl, add the butter and cream cheese and mix on medium high until light and fluffy
  15. Reduce mixer speed and begin adding 1/2 cup of powdered sugar at a time mixing well between each addition
  16. Add vanilla and key lime juice to icing, gradually increase the speed of the mixer back to a medium-high setting and allow to continue mixing for another 90-120 seconds ensuring that all powdered sugar has been incorporated

Notes

This recipe usually takes 4 cups of powdered sugar. If you find the consistency too thick add a tablespoon of extra powdered sugar at a time until you reach your desired consistency

Nutrition Information:
Yield: 20 Serving Size: 1
Amount Per Serving: Calories: 715Total Fat: 21gSaturated Fat: 12gTrans Fat: 1gUnsaturated Fat: 7gCholesterol: 74mgSodium: 350mgCarbohydrates: 133gFiber: 0gSugar: 120gProtein: 3g

The nutritional values above are auto calculated by a nutrition program and can vary based on brands of ingredients used.

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13 Comments

  • Beth
    July 8, 2020 at 10:28 am

    My daughter and I love key lime! She’ll be so excited to make this! Can’t wait! I’m so excited!

    Reply
    • Kerri
      July 8, 2020 at 10:38 am

      yay! it’s quickly become a favorite in our house!

      Reply
  • Vikki
    July 9, 2020 at 3:26 am

    Can’t wait to make this, looks so heavenly!

    Reply
  • Suzy
    July 9, 2020 at 12:45 pm

    That sauce is perfect over the cake! Makes it so moist! The flavor is amazing!

    Reply
  • katerina @ diethood.com
    July 10, 2020 at 11:16 am

    I would LOVE a slice of this amazing cake!!

    Reply
  • Marianne
    July 10, 2020 at 5:53 pm

    Making this for my in-laws birthday next week. No doubt, it will be a huge hit! Yum!!

    Reply
  • Sara Welch
    July 10, 2020 at 10:28 pm

    What a delicious dessert! Easily, a new favorite in our home; my husband loves your version!

    Reply
  • Joanna
    July 13, 2020 at 12:50 am

    My husband loves key lime pie but he’s not a fan of coconut. Would it be possible to omit toasted coconut from the recipe. I’d love to make it for him.

    Reply
    • Kerri
      July 13, 2020 at 8:20 am

      Hi Joanna!

      There is no coconut in the actual recipe. It’s merely a suggestion for those that like the coconut and lime flavor together. 🙂 Feel free to move forward with the recipe as directed and try not to eat it all at once! 😉

      Reply
  • Lillie
    July 13, 2020 at 11:50 pm

    Cream cheese icing?! I’m in!!!

    Reply
  • Farrah
    July 15, 2020 at 11:49 pm

    This looks so, so good! I’ve never tried making a key lime pie + I feel like I’d love it even more in sheet cake form! *-*

    Reply
  • Kathleen Ferragamo
    July 16, 2020 at 8:52 am

    Hi! Wondering can I freeze this? Should it be unfrosted to freeze it.

    Reply
    • Kerri
      July 19, 2020 at 9:35 pm

      Hi Kathleen! Yes, this can be frozen, however, I would recommend freezing this unfrosted.

      Reply

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