Elizabeth Poett's Lemon Cake with Lemon Curd Buttercream Frosting

Lemon Cake with Lemon Curd Buttercream Frosting

byElizabeth Poett
Total 1 hour and 30 minutes
Active 60 mins
Makes 8 to 10 servings
This cake is light and airy and fresh! It’s lemony but not overwhelmingly so. I love buttercream frosting and I love lemon curd, and so I decided to try combining them. The result was a frosting that is a dreamy blend of these two favorites: a fresh lemon flavor and a smooth, buttery frosting all in one. If you don't have time to make the lemon curd, it can be store-bought, but it’s fun to make. If you make it you’ll end up with a little bit of extra curd to enjoy on toast. My dad loves everything lemon so I make this cake for him on his birthday every year.
TIP: Lemon zest is the outermost layer of lemon peel. The white pith underneath is bitter, so when zesting, only take the yellow layer. Combining the lemon curd with the buttercream gives the cake a lemony flavor that’s not overwhelming.
Special Equipment
two 9-inch round cake pans
Special Equipment
two 9-inch round cake pans
  • 2 teaspoons shortening, for greasing pans
  • 2 tablespoons all-purpose flour or cake flour, for dusting pans
  • 2 1/2 cups cake flour
  • 1 1/2 teaspoons baking powder
  • 1/4 teaspoon kosher salt
  • 8 large eggs, at room temperature
  • 2 cups granulated sugar
  • 1/3 cup freshly squeezed lemon juice (from 2 to 3 lemons)
  • Zest of 2 lemons
Lemon curd
  • 4 large egg yolks, at room temperature
  • 1/2 cup granulated sugar
  • Zest of 1 lemon
  • 1/2 cup freshly squeezed lemon juice (from 3 to 4 lemons)
  • 6 tablespoons unsalted butter, cut into small cubes
  • 1 1/2 cups (3 sticks) unsalted butter, at room temperature
  • 1/2 teaspoon kosher salt
  • 5 cups powdered sugar
  • 3 tablespoons whole milk
  • 1 teaspoon vanilla extract
    1. To make the cake: Preheat the oven to 350°F.
    2. Grease two 9-inch round cake pans with some of the shortening. Place a circle of parchment paper over the bottom of each pan. Grease the parchment, then dust pans with flour. Set the pans aside.
    3. Sift the cake flour, baking powder, and salt together into a medium bowl and set aside. Carefully separate the egg yolks from the egg whites, putting the yolks into a small bowl and the whites into a large bowl.
    4. With a stand mixer on medium speed, beat the egg yolks and sugar for 4 to 5 minutes, until the mixture looks creamy and is thick enough to have a soft sheen to it. Add the lemon juice and lemon zest and continue to beat until fully incorporated. Add a third of the flour mixture at a time, beating well after each addition. Set the mixture aside.
    5. Beat the egg whites on high speed until they hold a stiff peak. Use a rubber spatula to fold the egg whites into the cake batter, scraping the sides of the bowl as you go. The batter should be both fluffy and thoroughly mixed. Divide the batter evenly between the cake pans and smooth the tops.
    6. Bake for 25 minutes or until a toothpick inserted comes out clean. Let cool for 15 minutes before turning the cakes out onto cooling racks.
    7. To make the lemon curd: Start by gathering your ingredients and place them on a flat surface next to the stovetop. In a heavy saucepan, combine the egg yolks, sugar, and lemon zest and whisk until smooth. Add the lemon juice and place the pan over medium heat. Cook, whisking constantly. Once the mixture begins to simmer and coats the back of a spoon, turn off the heat. Don’t let the mixture boil or it will curdle. Whisk in the butter cube by cube, whisking until melted. Continue whisking for 1 minute. Pour the curd into a bowl, cover, and refrigerate until completely cooled.
    8. To make the buttercream: In a stand mixer with the whisk attachment, cream the butter on high speed for 2 to 3 minutes. Add half of the lemon curd (about 1 cup). Mix for another minute. Turn the speed to low, add the salt, then add the powdered sugar 1 cup at a time. Once all the sugar is incorporated, add the milk and vanilla and beat on high speed for 4 to 5 minutes.
    9. To make the filling for the cake, combine 1/2 cup of lemon curd and 1 1/2 cups of buttercream frosting and mix thoroughly. Put about 2 tablespoons of filling directly onto the center of the serving plate. Place the first cake layer, upside down, onto the serving plate. Frost the top of this cake layer with a generous amount of filling. Place the second cake layer on top of the filling, right side up. Frost the top and sides of the entire cake with the remaining buttercream frosting. Decorate and serve.