Key Lime Sheet Cake
This Key Lime Sheet Cake is a bright, tangy dessert that’s moist, tender, and full of fresh lime flavor. Baked thin in a 13x18-inch pan, it stays incredibly soft thanks to a sweet-tart lime syrup that soaks into every bite. The rich cream cheese frosting adds the perfect balance, making each slice irresistibly delicious. This recipe serves a crowd, so it's perfect for potlucks, picnics, or your next family gathering. You’ll need 8 large limes for this recipe to provide plenty of fresh juice and zest for the cake, syrup, and frosting. Zest them all before juicing to make the most of your limes.
Ingredients
Cake
- 3 cups all-purpose flour
- 1 teaspoon baking soda
- 3/4 teaspoon fine grain sea salt or kosher salt
- 1 cup buttermilk at room temperature
- 1/2 cup fresh lime juice from 3 large limes
- 1 cup unsalted butter at room temperature
- 1 3/4 cups granulated sugar
- 3 tablespoons lime zest from 3 large limes
- 1 teaspoon vanilla extract
- 4 large eggs at room temperature
Lime syrup
- 1/2 cup granulated sugar
- 1/4 cup fresh lime juice from 2 large limes
Cream cheese frosting:
- 8 oz. cream cheese at room temperature
- 1/2 cup unsalted butter at room temperature
- 3 tablespoons fresh lime zest from 3 large limes
- 1/4 teaspoon fine grain sea salt or other fine grain salt
- 4 cups powdered sugar
Toppings
- 1 teaspoon lime zest
- 1 lime cut into thin wheels
- 4 large fresh strawberries optional
Instructions
Cake
- Preheat the oven to 350°F. Coat a 13x18-inch sheet pan with flour based baking spray, or grease and flour the pan.
- In a large mixing bowl, whisk together the flour, baking soda, and salt. In a large glass measuring cup with a pour spout, mix together the buttermilk and lime juice. Set aside.
- In the bowl of an electric mixer fitted with the paddle attachment, beat together the butter and granulated sugar until light and fluffy, about 3 minutes. Add the lime zest and vanilla extract. Beat again to combine. Add eggs one at a time, beating well after each addition. Scrape down the bowl occasionally to ensure even mixing.
- With the mixer on low speed, add the flour mixture and the buttermilk mixture alternately to the creamed butter mixture; begin and end with flour. Scrape down the bowl and beat again briefly.
- Spread the batter evenly into the prepared pan. Bake for 18-24 minutes or until a toothpick tester inserted near the center comes out clean.
Lime syrup
- Combine the sugar and lime juice in a microwaveable bowl. Microwave on 100% power for 1 minute; stir well until the sugar dissolves. If sugar granules are still present, microwave an additional 30 seconds and stir again.
- When the cake is done, use a fork to poke holes all over the cake. Using a pastry brush, cover the entire cake evenly with the lime syrup. Allow the cake to cool in the pan completely on a wire rack, about 1 hour.
Cream cheese frosting
- In the bowl of an electric mixer fitted with the whip attachment, beat the cream cheese and butter until fluffy, about 3 minutes. Add the lime zest and salt, and then mix again. Add the powdered sugar one cup at a time, beating well after each addition. Beat on high speed until the mixture is light and fluffy.
- Cover the entire cake with the cream cheese frosting.
Toppings
- Sprinkle lime zest over the frosting (or grate the zest of a lime directly onto the frosting as in the video).
- Arrange lime wheels in the corners and in the center of the cake. Slice the strawberries within 1/4 inch of the green tops; fan them slightly and arrange on top of the cake, if using.
Notes
- 9x13 Pan Version (Half Recipe): If you're serving a smaller crowd or just yourself, halve all of the ingredients and bake in a greased 9x13-inch cake pan. Use one with high sides, and not a jelly roll style pan. Increase the bake time slightly to 28-30 minutes. The cake will be thicker, plusher, more like a traditional party cake than a thin sheet cake.
- Limes: You don’t need to use key limes for this Key Lime Sheet Cake—regular (Persian) limes work just fine! While key limes have a more intense, slightly floral tartness, they can be harder to find and require juicing a lot more of them to get the same amount of juice. Regular limes provide plenty of bright, citrusy flavor. If you want to get closer to the key lime flavor, you can use bottled key lime juice, but fresh lime juice (of any variety) will still make a delicious cake!
- Perfect Lime Slices: For ultra-thin, even lime slices to use as a garnish, a mandoline slicer is your best friend! But be careful, those things are sharp! Set it to a thin setting and carefully slice the lime for beautiful, delicate rounds. If using a knife, make sure it’s very sharp to avoid crushing the lime.
- Even Better the Next Day: This cake tastes even more incredible the next day! As it sits, the oils from the lime zest infuse into the cake and frosting, deepening the citrus flavor and making every bite even more vibrant and delicious. If you have time, make it a day ahead for the best results.
- Storage: Store the cake covered in the refrigerator for up to 5 days. Let it sit at room temperature for about 30 minutes before serving for the best flavor and texture.
Tried this recipe?Let us know how it was!