Duncan Hines Key Lime Cake Recipe: Zesty Citrus Layers With Creamy Frosting

This key lime cake transforms a simple box mix into a creamy, citrus-infused masterpiece that tastes homemade. The secret lies in adding fresh lime zest and juice to the batter, creating bright, tangy layers that stand out.

The frosting takes it further with a smooth, velvety texture that balances the zesty cake perfectly. Using a Duncan Hines base ensures consistent, moist results every time, while the lime elements add a refreshing twist.

Each bite delivers a burst of tropical flavor, with the frosting providing a rich, creamy contrast to the light, airy cake. It’s an effortless way to impress with minimal effort.

Ideal for summer gatherings or whenever you crave a taste of the Florida Keys. This recipe makes it simple to achieve bakery-quality results at home.

Ingredients for Duncan Hines Key Lime Cake

Transform a box mix into bakery-worthy citrus perfection with these simple additions.

The cake mix base is Duncan Hines Classic Yellow—it has the right texture to hold up to the added lime. Fresh key limes are worth hunting down at Whole Foods or Latin markets, but regular limes work in a pinch (just add a bit more zest). For the cream cheese, Philadelphia brand gives that ultra-smooth frosting consistency. Bring all dairy to room temperature—cold cream cheese equals lumpy frosting (nobody wants that).

Out of key limes? Regular lime juice and zest will do—just use the same amounts. Bottled lime juice at half the quantity works if fresh isn’t available, but fresh zest is non-negotiable. No cream cheese? Full-fat Greek yogurt can sub in a 1:1 ratio, though the texture will be slightly different. The butter must be unsalted—salted throws off the balance with the tangy lime.

Cake stays moist wrapped at room temperature for 2 days, or refrigerate for up to 5 days. Frosted cake does best chilled. Freeze unfrosted layers for 1 month—thaw completely before frosting. Always zest limes before juicing (way easier).

Step-by-Step Instructions for Key Lime Cake

Here’s the method. Straightforward, tested, works every time.

Step 1: Prepare the Cake Batter

Preheat your oven to 350°F. In a large mixing bowl, combine the 1 box Duncan Hines Classic Yellow Cake Mix, 3 whole Large Eggs, 0.33 cup Vegetable Oil, 1 cup Water, 0.5 cup Key Lime Juice, and 2 tbsp Key Lime Zest.

Mix on medium speed for 2 minutes until the batter is smooth and fully combined. The lime zest and juice will give the batter a vibrant greenish tint and a fresh citrus aroma. Scrape down the sides of the bowl as needed to ensure even mixing.

This step infuses the cake with bright, zesty flavor. The acidity from the lime juice also helps create a tender crumb in the finished cake.

Step 2: Bake the Cake Layers

Pour the batter evenly into two greased and floured 9-inch round cake pans. Smooth the tops with a spatula to ensure even baking. Place the pans in the center of the preheated oven.

Bake for 25-30 minutes or until a toothpick inserted into the center of each cake comes out clean. The edges should pull away slightly from the pans, and the tops should be golden brown.

Allow the cakes to cool in the pans for 10 minutes before removing them to a wire rack to cool completely. Cooling completely is essential—if you try to frost warm cakes, the frosting will melt and slide off.

Step 3: Prepare the Cream Cheese Frosting

In a large bowl, beat the 8 oz Cream Cheese and 0.5 cup Unsalted Butter together until smooth and creamy. Use an electric mixer on medium speed for 2-3 minutes to ensure there are no lumps.

Gradually add the 3.5 cups Powdered Sugar, beating well after each addition. Then mix in the 1 tsp Vanilla Extract, 2 tbsp Key Lime Juice, and 1 tbsp Key Lime Zest. Beat for an additional 1-2 minutes until the frosting is light and fluffy.

The frosting should be spreadable but still hold its shape. If it’s too thick, add a teaspoon of milk or cream. If it’s too thin, add a bit more powdered sugar. The lime juice adds a tangy brightness that balances the sweetness perfectly.

Step 4: Frost and Finish the Cake

Once the cakes are completely cool, place one layer on a serving plate or cake stand. Spread a generous layer of frosting over the top of the first layer, then place the second cake layer on top.

Spread the remaining frosting over the top and sides of the cake, creating a smooth or textured finish as you prefer. For a decorative touch, garnish the top with additional Key Lime Zest or thin slices of lime.

The frosting’s creamy texture and tangy flavor will complement the moist, citrus-infused cake layers beautifully. Serve the cake at room temperature for the best flavor and texture.

Essential Equipment for This Recipe

Mixing Bowls

I always start with a large mixing bowl (my 5-quart Pyrex is perfect) for the cake batter. It gives plenty of room to incorporate all the ingredients without spills. A medium bowl works well for the frosting too.

Electric Mixer

An electric mixer is essential for achieving the right texture. I use my KitchenAid stand mixer with the paddle attachment for both batter and frosting. Hand mixers work, but require more effort for the 2-3 minutes of beating needed. 💪

Cake Pans

Use two 9-inch round cake pans that are at least 1.5 inches deep. I prefer non-stick with removable bottoms for easy release. Grease and flour them well, or use parchment paper for foolproof removal.

Measuring Tools

Accurate measurements matter, so I keep my dry measuring cups, liquid measuring cup, and measuring spoons handy. A microplane is perfect for zesting those key limes finely without bitter pith.

Cooling Rack

A wire cooling rack is a must for letting cakes cool evenly. I place mine over a baking sheet to catch any drips. Cool completely—about 1 hour—before frosting to prevent melting. ⏰

Offset Spatula

For smooth frosting, an offset spatula is my secret weapon. The angled blade helps spread frosting evenly on both layers and sides. I also use it to level the cake layers if they’ve domed during baking.

Frequently Asked Questions