This Key Lime Cake recipe makes a moist, tender 9 x 13-inch citrus cake with lemon cake mix, lime gelatin, orange juice, vegetable oil, and eggs. A buttery Key lime glaze soaks into the warm cake, while creamy Key lime cream-cheese frosting adds a rich, tangy finish; the recipe yields about 12–16 servings.
Plan on 20–25 minutes of preparation, 35–40 minutes of baking at 350°F (175°C), and 30–60 minutes for cooling and finishing. Every bite brings together bright lime flavor, gentle lemon sweetness, a soft crumb, and the irresistible richness of cream cheese frosting.
Jump to RecipeWhy You’ll Love This Recipe
This Key Lime Cake has the easy preparation of a boxed cake dessert but tastes like a thoughtfully made bakery treat. The lemon cake mix gives the crumb a gentle citrus base, while lime gelatin adds color, flavor, and a soft texture that stays pleasant after refrigeration.
The orange juice is an important part of the flavor balance. It rounds out the sharper Key lime notes with natural sweetness and gives the cake a sunny citrus character without making it taste like orange cake.
The warm glaze is the detail that makes this dessert special. As it travels through the fork holes, the butter, Key lime juice, and confectioners’ sugar create moist pockets throughout the cake instead of leaving all the lime flavor on the surface.
Finally, the frosting brings a cool, creamy contrast to the bright cake. This is a dependable dessert for potlucks, birthdays, spring gatherings, showers, family dinners, and any occasion that calls for a generous pan of fruit-forward cake.
Ingredients You’ll Need
Gather the ingredients before mixing so the batter comes together quickly and the cake can go straight into the oven. The traditional formula uses an 18.25-ounce lemon cake-mix box, though current 15.25-ounce boxes also work with a small difference in height.
- For the cake: one package of lemon cake mix, one 3-ounce package of lime gelatin, 3/4 cup orange juice, 3/4 cup vegetable oil, and four large eggs.
- For the glaze: 1/2 cup melted butter, 1/4 cup Key lime juice, and 1/2 cup confectioners’ sugar.
- For the frosting: one 8-ounce package softened cream cheese, 1/2 cup softened butter, one 16-ounce package confectioners’ sugar, 1/4 cup Key lime juice, and 1 teaspoon vanilla extract.
Key lime juice is available in bottles and is a practical choice when fresh Key limes are difficult to find. If you use fresh fruit, finely grated zest adds a fragrant citrus note without thinning the frosting.
How to Make It Step-by-Step
Step 1: Heat the oven to 350°F (175°C), then prepare a 9 x 13-inch baking pan by greasing and lightly flouring it. You can also line the pan with parchment, leaving a little overhang to make lifting the cooled cake easier.
Step 2: Add the lemon cake mix, lime gelatin, orange juice, vegetable oil, and eggs to a large bowl. Beat for about 1 minute on low speed and then 2 minutes on medium speed, stopping to scrape the bowl if needed, until the batter looks smooth and evenly blended.
Step 3: Pour the batter into the prepared pan and spread it into an even layer. Bake for 35–40 minutes, watching for a center that springs back lightly and testing with a toothpick that should come out clean or with a few moist crumbs.
Step 4: Prepare the glaze while the cake is finishing or immediately after it comes from the oven. Whisk the melted butter, Key lime juice, and confectioners’ sugar until the mixture is smooth and pourable.
Step 5: While the cake is still hot, prick the surface repeatedly with a fork or skewer. Make holes across the whole cake rather than concentrating them in one area, since the glaze needs pathways to spread through the crumb.
Step 6: Pour the glaze slowly and evenly over the warm cake. Pause briefly if needed so it can absorb, then direct any remaining glaze toward dry-looking areas for a consistently moist interior.
Step 7: Set the glazed cake aside and let it cool completely, allowing 30–60 minutes. Do not spread the cream-cheese frosting on a warm cake, because heat can soften the frosting and cause it to slide or melt.
Step 8: Beat the softened cream cheese and butter until creamy and smooth. Gradually add the 16-ounce package of confectioners’ sugar, then mix in the Key lime juice and vanilla extract until the frosting is fluffy and spreadable.
Step 9: Spread the frosting over the cooled cake in a generous, even layer. Chill the cake before slicing when you prefer firmer frosting, tidy squares, and a cooler, more refreshing dessert.
Pro Tips for the Best Texture
The glaze must go on while the cake is hot. This timing allows the warm crumb to absorb the buttery lime mixture and is responsible for the cake’s characteristic moist, citrusy interior.
Use room-temperature cream cheese and butter for the frosting. Soft ingredients blend more smoothly, reduce lumps, and help the confectioners’ sugar incorporate without requiring excessive mixing.
- Measure the orange juice and vegetable oil carefully rather than estimating.
- Do not overbake; begin checking near the lower end of the 35–40 minute range.
- Let the cake cool fully before frosting, even if the pan still feels slightly warm.
- Add fresh Key lime zest for fragrance, but avoid extra juice in the frosting.
- For a modern 15.25-ounce cake-mix box, use the listed liquids exactly as written and check the cake a few minutes early.
The older 18.25-ounce cake-mix size produces the traditional result and a somewhat fuller cake. A 15.25-ounce box still works, but the finished cake may be slightly shorter, so rely on the visual doneness cues rather than adding extra ingredients.
Storage and Slicing
Because the frosting contains cream cheese, cover the cake and refrigerate it. Chilling also makes the frosting easier to cut cleanly and gives the citrus flavor time to settle into the cake.
For the neatest squares, use a sharp knife and wipe the blade between cuts. Let each slice sit briefly at room temperature if you prefer a softer crumb and a less-cold frosting.
The cake is well suited to advance preparation. Bake and glaze it, cool it completely, frost it, and refrigerate it until serving; this schedule keeps the process manageable for parties and family meals.
Serving Ideas and Variations
Serve the cake chilled or slightly cool, depending on your preference. A little freshly grated Key lime zest over the frosting adds color and makes the citrus aroma noticeable before the first bite.
For a simple presentation, cut the cake into 12 large squares. For a dessert table or buffet, cut it into 16 smaller pieces so guests can enjoy a portion alongside other sweets.
You can finish each piece with a thin lime slice or a small curl of zest. Keep the decoration restrained, because the cake’s creamy frosting and bright green citrus notes already provide an attractive finish.
The recipe’s lemon, lime, and orange combination is balanced rather than aggressively tart. That makes it approachable for guests who enjoy citrus desserts but prefer a soft, sweet cake with tangy accents instead of a strongly sour flavor.
Key Lime Cake Recipe
Ingredients
Method
- Heat the oven to 350°F (175°C). Grease and lightly flour a 9 x 13-inch baking pan, or line it with parchment paper.
- Combine the lemon cake mix, lime gelatin, orange juice, vegetable oil, and eggs in a large mixing bowl. Beat with an electric mixer for about 1 minute on low speed, then 2 minutes on medium speed, until the batter is smooth.
- Pour the batter into the prepared pan and smooth the top. Bake for 35–40 minutes, until the center springs back lightly and a toothpick comes out clean or with a few moist crumbs.
- While the cake is still hot, prick the entire surface repeatedly with a fork or skewer. This creates channels for the warm glaze to move into the cake.
- Whisk the melted butter, Key lime juice, and 1/2 cup confectioners’ sugar together until smooth. Pour the glaze evenly over the warm cake, giving it time to seep through the holes.
- Allow the glazed cake to cool completely before frosting. Cooling usually takes 30–60 minutes, depending on the pan, room temperature, and airflow.
- Beat the softened cream cheese and softened butter until smooth. Gradually add the 16-ounce package of confectioners’ sugar, then beat in the Key lime juice and vanilla extract.
- Spread the frosting over the completely cooled cake. Refrigerate before slicing if you want a firmer frosting and cleaner pieces.
Notes
Final Thoughts
This Key Lime Cake recipe delivers a moist sheet cake, a buttery citrus glaze, and a smooth cream-cheese frosting in one straightforward dessert. The boxed cake base keeps preparation simple, while the warm glaze and fresh lime flavor make the finished result taste carefully made.
Remember the two most important details: pour the glaze over the cake while it is hot, and wait until the cake is completely cool before frosting. With those steps in place, you will have tender, flavorful squares with a creamy finish and plenty of bright Key lime character.
Prepare it for a gathering, refrigerate it for clean slices, and add a touch of Key lime zest just before serving. This cheerful fruit dessert is easy to share and memorable enough to become a regular favorite.
