The Ultimate Moist Key Lime Cake Recipe

There’s something so refreshing about the taste of citrus, especially in a dessert. If you’re a fan of vibrant, tangy flavors paired with sweetness, you’re going to love this Ultimate Moist Key Lime Cake recipe.

It’s perfect for any occasion—whether you’re celebrating a special event, hosting a family gathering, or simply craving something sweet with a kick of lime. Let’s dive into what makes this cake so irresistible!

Why You’ll Love This Key Lime Cake

What sets this cake apart is its incredible texture—it's light, airy, and incredibly moist. But that’s not all. The burst of fresh lime juice and the addition of lime jello in the cake batter give it that perfect tanginess, while the lime buttercream icing ties it all together with a creamy, rich finish.

Whether you’re an experienced baker or a beginner in the kitchen, this recipe is simple to follow, with easy-to-find ingredients that pack a punch of flavor.

Let’s talk ingredients. For the perfect texture and flavor, you'll need:

Cake Ingredients:

• 3 cups cake flour

• 2 1/2 tsp baking powder

• 3 oz lime Jello (for extra lime flavor and color)

• 1/2 cup unsalted butter (room temperature)

• 1/2 cup butter-flavored shortening (adds a subtle richness)

• 1 3/4 cup granulated sugar

• 1 tsp salt

• 3 large eggs (room temperature)

• 2 large egg yolks (room temperature)

• 1 tbsp vanilla extract

• 4 tbsp fresh lime juice

• 1 1/3 cup buttermilk (room temperature, for the perfect moist texture)

Lime Buttercream Icing:

• 4 cups powdered sugar

• 1/2 cup unsalted butter (softened)

• 8 oz cream cheese (softened, to give that tangy, smooth texture)

• 1 tsp vanilla extract

• 1 tbsp lime juice

• Zest of 1 lime (for a citrusy punch)

Step-by-Step Instructions

1. Preheat & Prep

Start by preheating your oven to 350°F (175°C). Grease and flour three 8-inch round cake pans or use parchment paper to line the bottoms for easy cake removal.

2. Mix the Dry Ingredients

In a medium bowl, whisk together the cake flour, baking powder, and lime Jello. Set aside.

3. Cream the Butter & Sugar

In a large mixing bowl, cream together the unsalted butter and butter-flavored shortening, then slowly add in granulated sugar. Beat on medium speed until the mixture is light and fluffy, about 4-5 minutes.

4. Add the Eggs

Add the eggs and egg yolks one at a time, beating well after each addition. Then mix in the vanilla extract, lime juice and lime zest.

5. Combine the Wet & Dry

Alternate adding the flour mixture and the buttermilk to the butter mixture, starting and ending with the flour. Beat on low speed just until combined.

6. Bake

Divide the batter evenly among the prepared cake pans. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean. Allow the cakes to cool in the pans for about 10 minutes, then transfer them to a wire rack to cool completely.

7. Make the Lime Buttercream Icing

While the cakes are cooling, it’s time to make that luscious lime buttercream icing. In a large bowl, beat the softened butter and cream cheese together until smooth (at least 10 minutes). Gradually add the powdered sugar, beating on low speed to prevent a sugar cloud! Mix in the vanilla extract, lime juice, and lime zest until everything is well-combined and smooth.

8. Assemble the Cake

Once your cakes are completely cooled, it’s time to frost! Split your cakes so that there are 4 total layers. You may use all 4 layers or just 3! Place the first cake layer on a serving plate or cake stand. Spread a thick layer of lime buttercream over the top, then place the second layer on top. Repeat with the third layer and then 4th if using 4 layers. Finally, frost the top and sides of the cake, smoothing with a spatula for a clean finish.

Why Lime Jello?

You might be wondering why I’m using lime Jello in the cake batter. Lime Jello is a little baking secret! Not only does it give the cake an extra punch of lime flavor, but it also adds moisture and a fun, light green color that really makes this cake stand out.

Pro Tips for the Best Key Lime Cake

1. Room Temperature Ingredients: Always make sure your butter, eggs, and buttermilk are at room temperature. This ensures the batter blends together smoothly and creates a fluffy texture.

2. Fresh Lime Juice and Zest: Using fresh lime juice and zest is key to getting that bright, authentic lime flavor.

3. Chill Before Serving: If you can, let the cake chill in the refrigerator for at least an hour after frosting. This helps the buttercream set and makes slicing the cake a breeze.

Serving Suggestions

This Ultimate Key Lime Cake is perfect served on its own, but if you’re feeling extra indulgent, you can garnish it with extra lime zest, or even serve it with a dollop of whipped cream. It pairs wonderfully with a cup of tea or coffee, or a cold glass of milk for a refreshing dessert experience.

Storing the Cake

This cake can be stored in an airtight container in the refrigerator for up to 5 days. The buttercream will firm up in the fridge, so be sure to bring the cake to room temperature before serving to enjoy that soft, creamy icing.

If you’re a fan of citrusy desserts, this Ultimate Moist Key Lime Cake is a must-try! It’s packed with flavor, incredibly soft, and topped with the creamiest lime buttercream icing. Perfect for birthdays, gatherings, or just a special treat for yourself. Give it a try, and don’t forget to let me know how it turned out in the comments!