This lemon cake is so moist and velvety! It's filled with homemade lemon curd and topped silky lemon buttercream frosting.
Prep Time 35 minutesminutes
Cook Time 40 minutesminutes
Total Time 1 hourhour15 minutesminutes
Servings 12
Ingredients
For the filling
1teaspoonunflavored gelatin powder
⅔cup(160ml)fresh lemon juice, from about 2 lemons
4large eggs
2large egg yolks
1cup(200g)granulated sugar
1tablespoonlemon zest, from about 1 lemon
¼cup(56g)unsalted butter
For the cake
2cups(400g)granulated sugar
2tablespoonslemon zest
½cup(120ml)canola oil, or vegetable oil
½cup(113g)unsalted butter, room temperature
4large eggs, room temperature
1teaspoonvanilla extract
3cups(360g)cake flour
1tablespoonbaking powder
1teaspoonground ginger
½teaspoonsalt
¾cup(180ml)whole milk, room temperature
¼cup(60ml)fresh lemon juice
Make the frosting
1 ½cups(339g)unsalted butter, softened
⅛teaspoonsalt
4cups(480g)confectioners' sugar, sifted
2tablespoonsheavy cream
⅓cup(113g)lemon curd, taken from the filling above
Instructions
Make the filling
In a small bowl, sprinkle the gelatin over 1 tablespoon of the lemon juice and set aside.
In a small saucepan combine the eggs, egg yolks, and sugar. Whisk until frothy and smooth, about 4 minutes. Whisk in the remaining lemon juice and lemon zest.
Cook over medium-low heat, stirring constantly, until thickened, about 7-10 minutes. You'll know the curd is ready when it coats the back of a wooden spoon and is about the thickness of pudding.
Immediately remove from heat and stir in the gelatin until fully dissolved and incorporated. Stir in the butter until fully combined.
Press the curd through a fine-mesh sieve into a bowl. Cover the bowl with plastic wrap. Make sure the wrap is touching the surface of the curd to prevent a skin from forming.
Refrigerate for at least 4 hours or up to 24 hours. The curd will be thick once set. Stir it vigorously to loosen before using.
Make the cake
Preheat the oven to 350°F. Grease the inside bottom and sides of two 9-inch round pans. Line the bottom of the pans with parchment paper cut to fit. Lightly grease the parchment paper. Dust the inside bottom and sides of the pan with flour, then tap out any excess. Wrap the pans in wet bake even strips. Set aside.
Using a stand mixer with the paddle attachment or a handheld electric mixer, beat the sugar and lemon zest together on medium speed for at least 5 minutes. This helps extract the oils from the zest resulting in more lemon flavor.
Add the oil and butter and mix on medium-high speed until light and fluffy, about 5 minutes. Add the eggs, one at a time, mixing for 20 seconds after each addition. Beat in the vanilla.
Combine the flour, baking powder, ginger, and salt in a medium bowl. Stir with a whisk and add half to the butter mixture. Beat on low speed until the flour is almost fully incorporated.
Mix in the milk and lemon juice, followed by the remaining flour mixture, and beat on low until just combined. Take care not to over mix.
Divide the batter evenly between the prepared pans and bake for 25-30 minutes, until a toothpick inserted into the center comes out with only a few moist crumbs attached.
Cool in the pans for 10 minutes then transfer to a wire rack and allow to cool completely before frosting.
Make the frosting
In the bowl of a stand mixer fitted with the paddle attachment or a large mixing bowl with a handheld electric mixer, beat the butter and salt on medium-high speed until creamy and pale in color, about 5 minutes.
Add half of the confectioners' sugar and beat on low speed just until the sugar has fully moistened, then turn the speed up to medium-high and beat until well incorporated, about 3-5 minutes.
Add the remaining confectioners' sugar and beat on low speed just until the sugar has fully moistened, then turn the speed up to medium-high and beat until well incorporated, about 3-5 minutes.
Turn the mixer on low speed and slowly add the heavy cream. Turn the mixer up to medium-high and beat until the cream is well incorporated, about 3-5 minutes.
Add the lemon curd and gently mix at low speed until fully combined.
Assemble the cake
Place one cake layer onto a serving platter. Pipe a dam of frosting around the outer edge. Spread the remaining lemon filling inside the dam in an even layer.
Top with the second cake layer. Then, cover the top and sides of the cake with frosting. Immediately refrigerate the cake until firm, about 1 hour.
Decorate with lemon slices just before serving.
Notes
Gelatin: This will stiffen the curd to allow it to hold up under the weight of the cake. It also prevents it from separating the buttercream when added to the frosting. If you're adamant about not using it, leave it out and be sure you cook the curd long enough to become super thick, 180°F.
Lemon juice: I prefer freshly squeezed lemon juice. It's milder than bottled. You can use bottled if it is an absolute must.
Oil: Don't substitute the oil with more butter. The oil in this cake is key to its light and moist texture. Use any flavorless oil you prefer.
Cake flour: While I have a homemade cake flour recipe, I highly recommend using the real stuff. There's less protein and that yields a supremely soft crumb. All-purpose flour will not give the same results. I tested both and cake flour is the true winner!
Ginger: Omit it if you must but I find it enhances the lemon flavor. It doesn't taste gingery in any way.
Bake even strips: Wrap that cake pans in bake even strips. These are strips of cloth that are soaked in water. They help the cake to bake evenly so you get tall flat layers.
Cake pans: I've only tested this recipe in two 9-inch pans. However, I imagine three 8-inch pans will work just as well. The layers will be thinner and the bake time may need to be adjusted. Keep a close eye on them and start checking for doneness once the top center no longer looks wet. Don't open the oven door before then or the cakes will fall!
For any other pan sizes, you can use online cake pan calculators to guide you in how to make adjustments.
Make ahead tip
The fully assembled cake will keep for up to 5 days covered tightly and stored in the refrigerator.
The cake layers can be made a day in advance. Once cooled, wrap tightly in plastic wrap and refrigerate.
The frosting and lemon curd can also be made a day in advance. Cover tightly and keep refrigerated. Bring the frosting to room temperature and re-whip before using.
Both the frosted cake and unfrosted cake layers will keep for up to 3 months stored in the freezer. Wrap tightly in plastic wrap followed by two layers of aluminum foil. Thaw overnight in the refrigerator then bring to room temperature before serving/using.