Key Lime Cake

5 from 1 vote

This Key Lime Cake is a showstopper for any fans of key lime pie. It's got all the elements - graham cracker layers, smooth key lime cream cheese frosting, and tart key lime curd all combined with my buttery soft layers of vanilla cake flavors with even more lime zest.

Prep Time45

Cook Time30

Total Time1 15

Course: Dessert

Cuisine: American

Servings: -16 servings

Author: Amy Nash

Ingredients

Graham Cracker Crust

2 1/2 cups graham cracker crumbs (about 20 full graham cracker sheets) + extra for decorating the cake
1/2 cup salted butter melted
1/3 cup granulated sugar

Cake

3 cups (384g) cake flour
2 cups (400g) granulated sugar
2 1/2 teaspoons baking powder
1/2 teaspoon baking soda
1 teaspoon salt
1/2 cup (113g) salted butter room temperature & cubed
1/2 cup (118ml) vegetable oil or canola oil
3 large eggs room temperature
1 1/3 cups (315ml) buttermilk room temperature
2 Tablespoons lime zest
2 Tablespoons key lime juice
1 Tablespoon pure vanilla extract

Key Lime Curd

3/4 cup granulated sugar
1/2 cup key lime juice
1 Tablespoon lime zest
4 large egg yolks
4 Tablespoons salted butter

Frosting

1 cup salted butter
8 ounces full-fat cream cheese
6 cups powdered sugar
2 Tablespoons key lime juice
1 Tablespoon pure vanilla extract
1/2 teaspoon lime zest
Fresh lime slices for garnish

Instructions

Preheat the oven to 350°F. Line three 8-inch cake pans with parchment paper circles and spray with baking spray or brush with cake release.
Combine graham cracker crumbs, sugar, and melted butter until evenly moistened. Evenly divide the graham cracker mixture between the cake pans and press with a flat-bottomed cup to form a crust layer in the bottom of each cake pan. Bake for 8 minutes to set the crust, then remove and set aside while preparing the cake batter.
2 1/2 cups graham cracker crumbs, 1/2 cup salted butter, 1/3 cup granulated sugar
In a large mixing bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.
3 cups (384g) cake flour, 2 cups (400g) granulated sugar, 2 1/2 teaspoons baking powder, 1/2 teaspoon baking soda, 1 teaspoon salt
With an electric mixer running on low speed, add one tablespoon of the softened butter at a time, mixing well until incorporated before adding another tablespoon of butter until all of the butter has been added. The mixture should look sandy and dry with coarse crumbs.
1/2 cup (113g) salted butter
Add the oil and continue to mix on low speed until the flour mixture has been evenly moistened. Add the eggs, buttermilk, lime zest, lime juice and vanilla extract, mixing and stopping to scrape the bottom and sides of the bowl until evenly combined.
2 Tablespoons lime zest, 1/2 cup (118ml) vegetable oil or canola oil, 3 large eggs, 1 1/3 cups (315ml) buttermilk, 1 Tablespoon pure vanilla extract, 2 Tablespoons key lime juice
Divide the cake batter evenly between the prepared cake pans, pouring it over the graham cracker crumb layer.
Bake for 28 to 32 minutes or until a toothpick or skewer inserted into the center of each cake layer comes out clean with just a few crumbs clinging to it. Cool completely before assembling the cake. These can be made up to 2 months in advance and wrapped tightly in plastic wrap, then frozen until ready to thaw and assemble the cake.
In a medium saucepan, whisk together the sugar, lime juice, lime zest, and egg yolks. Add the butter and cook over medium-low heat, whisking or stirring constantly, until the butter has melted and the curd has thickened enough to coat the back of a spoon, about 10-14 minutes. Pour the curd through a fine mesh strainer and cover with plastic wrap pressed directly against the curd. Cool completely or chill before using.
3/4 cup granulated sugar, 1/2 cup key lime juice, 1 Tablespoon lime zest, 4 large egg yolks, 4 Tablespoons salted butter
To make the frosting, beat the butter and cream cheese together in a large mixing bowl until completely combined and smooth. Add the powdered sugar, lime juice, vanilla, and lime zest, then mix just until smooth and combined. It should be light, fluffy, and spreadable, but do not overmix or the frosting can become runny.
1 cup salted butter, 8 ounces full-fat cream cheese, 6 cups powdered sugar, 2 Tablespoons key lime juice, 1 Tablespoon pure vanilla extract, 1/2 teaspoon lime zest
To assemble, level off the cake layers if needed. Place one layer on a cake plate and spread with a thin layer of the frosting (this helps prevent the lime curd from soaking into the cake layers). Transfer 2 cups of the frosting to a piping bag fitted with a large open tip and pipe a border around the top edge of the cake to create a barrier to hold in the lime curd. Spread half of the lime curd onto the cake and spread it into an even layer. Repeat with the second cake layers, frosting, and remaining lime curd.
Add the top cake layer and frost, reserving enough frosting to pipe swirls of frosting around the top edges. To decorate, press extra crushed graham cracker crumbs into the frosting about 1/3 of the way up the cake. Pipe frosting swirls around the top using the Wilton 1M tip or other decorative tip. Finish with fresh lime slices for garnish. Freeze the entire cake for 20 minutes or refrigerate 1 hour to help set the frosting before slicing and serving.
Fresh lime slices

Notes

Storage: Because there is cream cheese in the frosting, you should store the cake in the fridge for up to 5 days. Let it come to room temperature before serving for the best taste and texture. Cakes with cream cheese based frosting can sit out for about 2 hours at room temperature before they need to be refrigerated.
Freezing: This cake freezes well for up to 2 months. I recommend flash freezing individual slices, then wrapping them with plastic wrap and transferring to a freezer-safe container for longer term storage. Let the cake thaw overnight in the fridge then sit out at room temperature for 1-2 hours before serving.
Substitutions: You can use the same amount of all-purpose flour in place of cake flour. If you don't have any buttermilk, you can replace it with half sour cream and half milk.
9-inch cake pans: Bake for 22 to 24 minutes.
9x13-inch pan: Bake for 30 minutes.
Two-layer cake: If using 9-inch pans, bake for 25 to 28 minutes. If using 8-inch pans, bake for 35-38 minutes.

Nutrition

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