Lemon Raspberry Layer Cake with Lemon Buttercream
 
 
A luscious lemon raspberry layer cake - a light white cake brushed with tart lemon syrup and filled with layers of lemony buttercream and homemade lemon curd - a lemon lover's dream!
Yield: 10-12 servings
Ingredients
For the cake
  • 6 tbsp (86 g) unsalted butter, room temperature
  • 6 tbsp (75 g) neutral oil
  • 1⅓ cups (270 g) sugar, divided
  • 2 tsp vanilla extract
  • zest of 1 lemon
  • 3 cups (360 g) cake flour
  • 1 tbsp baking powder
  • ½ tsp kosher salt
  • 1 cup (240 g) milk, room temperature
  • 6 large egg whites
For the lemon curd
  • 1 cup (240 g) fresh lemon juice
  • ¼ cup (56 g) unsalted butter
  • 2 tbsp heavy cream
  • 4 large eggs
  • 2 large egg yolks
  • 1 cup (200 g) sugar
  • ½ tsp kosher salt
  • ½ tsp vanilla extract
For the buttercream
  • 1½ cups (300 g) sugar
  • ¾ cup (180 g) water
  • 4 large eggs
  • 2 large egg yolks
  • 3 cups (681 g) unsalted butter, room temperature, cut into 1-inch chunks
  • ¼ tsp kosher salt
For the lemon syrup
  • ½ cup (120 g) fresh lemon juice
  • ½ cup (120 g) water
  • ¾ cup (150 g) sugar
For assembly
  • 1 pint (260 g) raspberries
Instructions
For the cake
  1. Heat oven to 350F. Grease three 9-inch round cake pans and line with parchment paper. Set aside.
  2. In a stand mixer fitted with the paddle attachment, cream together the butter, oil, and 1 cup of the sugar (200 g) for 2-3 minutes or until light and creamy. Scrape down the sides of the bowl. Add in the vanilla and lemon zest. Beat again for 1-2 minutes, or until combined.
  3. In a medium bowl, whisk together the flour, baking powder, and salt. With the mixer running on low, add about a third of the flour mixture to the bowl. Once combined, add half of the milk and mix until incorporated. Scrape down the sides of the bowl. Add half of the remaining flour mixture, followed by the rest of the milk. Scrape down the bowl again. Add the rest of the flour mixture and mix until incorporated. Transfer the batter to a large bowl.
  4. If you have a second mixer bowl, then use it here. If not, thoroughly clean the mixer bowl that you just used to mix the batter. No batter should remain on the bowl as the fat will inhibit the eggs from whipping.
  5. Place the egg whites in the clean mixer bowl and mix with the whip attachment on medium speed for 3-4 minutes or until they form soft peaks. With the mixer running, slowly add in the remaining ⅓ cup of sugar. Whip again for 1-2 minutes or until the whites form glossy, stiff peaks.
  6. Use a rubber spatula to fold a third of the egg whites into the batter. Add the remaining egg whites and gently but thoroughly fold them in. Divide the batter evenly among the prepared baking pans.
  7. Bake for 20-25 minutes, or until each cake starts to pull away from the sides of the pan and it springs back in the center when poked. Allow to cool in the pans on a wire rack for 30 minutes. Then turn the cakes out of the pans and allow to cool completely.
For the lemon curd
  1. Combine the lemon juice, butter, and heavy cream in a medium saucepan over medium-high heat and bring to just under a boil.
  2. Meanwhile, in a heatproof bowl whisk together the eggs, egg yolks, and sugar. Gradually whisk the hot lemon juice mixture into the egg mixture, whisking constantly.
  3. Once all of the hot liquid has been added, pour the entire mixture back into the saucepan. Over medium heat cook, stirring constantly to scrape the bottom of the pan with a spoon, for 5-8 minutes or until the mixture thickens significantly and coats the back of a spoon.
  4. Remove from the heat and pour through a fine-mesh sieve to remove any cooked egg pieces. Whisk in the salt and vanilla. Cover with plastic wrap and refrigerate until cold.
For the buttercream
  1. Stir together the water and sugar in a small saucepan. Bring to a boil over high heat and cook, without stirring, until the syrup reaches 238F.
  2. Meanwhile, fit the stand mixer with the whisk attachment and beat the eggs and egg yolks for 3-4 minutes or until pale.
  3. Once the syrup has come to temperature remove it from the heat and, with the mixer running on low, slowly add it to the eggs. Once it has all been added increase the mixer speed to medium and whip for 6-8 minutes or until the mixture has cooled to room temperature.
  4. With the mixer running on low, add in the butter a few chunks at a time. Once it has all been added, increase the mixer speed to medium and whip until it comes together, about 3-4 minutes. It may look curdled at first, but keep whipping and it will come together.
  5. Add the salt and whip until combined.
For the lemon syrup
  1. In a small saucepan, combine the lemon juice, water and sugar. Bring to a boil, stir until the sugar dissolves, and then remove from the heat. Allow to cool to room temperature.
To assemble
  1. Scoop 3 cups of the buttercream into a medium bowl. To this, add ½ cup of the lemon curd and whisk until combined. Set aside the remaining buttercream. Set aside ⅓ cup of lemon curd for decorating the top of the cake.
  2. If your cakes have domed, trim the top to level them. Place a spoonful of buttercream in the center of a 9-inch cardboard cake round. Top with one of the cake layers. Brush with a third of the lemon syrup.
  3. Top the cake with 1 cup of the curd-buttercream mixture and spread to the edges of the cake in an even layer using an offset spatula. Spoon ½ cup of the curd-buttercream mixture into a piping bag fitted with a ½-inch tip. Use this to pipe a layer of frosting around the perimeter of the cake to form a flood layer. Spread half of the lemon curd on top of the buttercream. Sprinkle half of the raspberries on top of the curd.
  4. Top with a second cake layer and press down lightly. Brush with half of the remaining lemon syrup. Spoon on a cup of the curd-buttercream mixture and spread to the edges of the cake using an offset spatula. Repeat the flood layer and then spread the rest of the curd on top. Set aside about 5 raspberries for the top of the cake. Sprinkle the remaining raspberries over the lemon curd.
  5. Place the third cake layer on top, top-side down. Brush with the remaining lemon syrup. Place in the refrigerator to firm up for at least 1 hour.
  6. Spoon 1 cup of the plain buttercream over the cake. Spread it on top and down the sides of the cake in a thin layer. This will be the crumb coat. Refrigerate for 30 minutes.
  7. Spread 1½ cups of the remaining buttercream on top of the cake and frost the top and sides as desired. Spread the reserved ⅓ cup of lemon curd on top of the cake in a thin layer. Use any remaining buttercream to decorate the top and/or sides of the cake. Garnish with the remaining reserved raspberries.
Notes
Recipe from Flour
Recipe by Joanne Eats Well With Others at https://joanne-eatswellwithothers.com/2023/03/lemon-raspberry-layer-cake-with-lemon-buttercream.html