This Key Lime Sheet Cake is a tart and sweet cake with a creamy frosting. Light, refreshing, and full of citrus flavor, it’s a favorite whenever it’s served—perfect for anyone who loves bright, tangy desserts.
I’m a huge fan of sheet cakes—everything from peanut butter and caramel apple to German chocolate and crème brûlée. After making a Key Lime Bundt Cake, I wanted a bright, citrusy sheet cake to enjoy all summer long. Key limes are small but pack an intense tartness that pairs beautifully with a sweet, creamy frosting.
The cake strikes a lovely balance of tart and sweet. The frosting is creamy and smooth, adding richness while enhancing the lime notes. Serve a slice with fresh berries or a light dollop of whipped cream for an extra-special treat.
If you enjoy citrus-forward desserts, this Key Lime Sheet Cake is a must-try. Its bright flavor and tender crumb make it a crowd-pleaser at gatherings, picnics, or casual weeknight desserts.
- 2 cups all-purpose flour
- 2 cups granulated sugar
- 1/2 cup butter
- 1/2 cup shortening
- 1/2 cup water
- 1/2 cup key lime juice
- 1/2 cup buttermilk
- 1/2 teaspoon baking soda
- 2 large eggs
- 1 teaspoon vanilla extract
- FROSTING
- 1/2 cup butter
- 4 tablespoons milk
- 2 tablespoons key lime juice
- 3 cups powdered sugar
- 1 teaspoon vanilla extract
- Preheat oven to 400°F (204°C). Grease a 15 x 10 x 1-inch baking sheet and set aside.
- In a large bowl, whisk together the flour and sugar; set aside.
- In a medium saucepan, combine 1/2 cup butter, 1/2 cup shortening, and 1/2 cup water. Bring to a boil. Once boiling, stir in the 1/2 cup key lime juice, then add the flour-sugar mixture and stir until combined.
- Stir in the buttermilk, then the baking soda, followed by the eggs, and finally the vanilla, mixing well between each addition until the batter is smooth.
- Pour the batter into the prepared baking sheet and bake at 400°F for about 20 minutes, or until a toothpick inserted into the center comes out clean.
- For the frosting: In a medium saucepan, combine 1/2 cup butter and 4 tablespoons milk and bring to a boil. Remove from heat and stir in 2 tablespoons key lime juice, 3 cups powdered sugar, and 1 teaspoon vanilla until smooth and spreadable.
- Allow the cake to cool for about 15 minutes, then poke holes across the top with a fork. While still slightly warm, spread the frosting evenly over the cake so it soaks into the holes and sets into a creamy layer.
Enjoy!