A sweet and tart treat, this Key Lime Cake is perfect for any occasion. It's so wonderfully tangy, moist, and fluffy with lime flavor infused throughout.
Preheat the oven to 350°F. Grease 3 (8-inch) round cake pans.
In a large bowl, whisk together flour, baking powder, salt, and baking soda.
In a medium mixing bowl or the bowl of a stand mixer fitted with the whisk attachment, beat the sugar, sour cream, and oil until combined, 1 to 2 minutes. Stopping to scrape down the sides of the bowl as needed. Add the eggs, one at a time, scraping down the bowl between additions, beat until well combined. Add the lime juice, zest, and vanilla and beat until combined.
Add the oil mixture to the flour mixture and beat until just combined. Divide the batter among the prepared cake pans. (if using a stand mixer, you can add the flour mixture into the oil mixture already in the bowl.)
Bake for 15 to 20 minutes or until the center of cakes are springy to the touch the sides are just starting to pull away from the pan. Let the cakes cool in the pan for 10 minutes then invert and cool completely on a wire rack.
For the frosting:
In a large mixing bowl or the bowl of a stand mixer fitted with the paddle attachment, beat the butter and cream cheese together on medium speed until creamy and well combined, about 1 minute.
With the mixer on low speed, gradually add the confectioners’ sugar alternating with a little bit of the lime juice. Stop occasionally and scrape down the bowl. Beat in the vanilla. Once combined, increase the speed to medium-low and beat until smooth and fluffy, about 1 minute.
For the Assembly:
Place 1 cup of frosting in a piping bag fitted with a star tip.
Place one cooled cake layer on a cake stand or serving plate. Top with 1 cup of frosting, spreading smoothly out to the edges. Place another cake layer on top and repeat with 1 cup of frosting. Top with final cake layer, and spread the remaining frosting all over the top and sides of the cake.
Pipe decorations on the top edge of cake with the reserved frosting. Garnish with thin lime slices, if desired. Chill for 30 minutes to set the frosting before serving. Cake can be covered at stored at room temperature for up to 5 days.
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Notes
If the tops of the cake layers come out domed, you can use a serrated knife to cut off the top of the domes so you can stack them evenly. If you’re concerned the layers will not be even, you can use cake strips. Cake strips work by keeping the outside edge of the pan cooler to ensure that the entire cake rises at the same rate, preventing a dome from forming in the middle. If you don’t want to purchase cake strips to make this key lime cake, see my guide on how to DIY cake strips.
I highly recommend using a scale to measure your flour as it’s the most accurate method and will prevent you from ending up with dense cake layers. If you don’t have a scale, fluff your flour with a spoon and spoon it into your cups before leveling it off with a knife. This method prevents you from overpacking the measuring cup.
When zesting a lime, stop zesting once you reach the white layer, as it’s bitter.
Give the cake pans a few gentle taps on the counter to burst any air bubbles in the batter.
Did you know that cold cake layers are easier to assemble? Cakes are more fragile when hot. If you’re worried about the cake breaking as you assemble it, make them ahead of time and place them in the refrigerator to chill them.
Be careful not to overmix the cake batter, as doing so will lead to a tough, dense cake.
For easy removal, line the bottoms of the round baking pans with parchment.
This recipe can also be made in a 13x9-inch pan for a quick and easy single-layer cake! Simply bake for 35 to 40 minutes or until lightly golden brown, the center of the cake springs back to the touch, and the sides are just starting to pull away from the pan.