Lemon Raspberry Cake with Swiss Meringue Frosting Recipe

Ingredients

Raspberry Jam

• 4 1/2 cups frozen raspberries
• 1/2 cup granulated sugar
• 1 tablespoon lemon juice
• 2 tablespoons cornstarch
• 2 tablespoons water
• 1 teaspoon vanilla extract

Lemon Cake Batter

• 1 1/2 cups granulated sugar
• 2 tablespoons fresh lemon zest, packed
• 3 cups cake flour
• 1 teaspoon fine sea salt
• 1 tablespoon baking powder
• 1 cup cubed unsalted European butter, room temperature
• 3 large eggs, room temperature
• 1 1/2 cups heavy cream
• 1/3 cup vegetable oil
• 2 tablespoons fresh lemon juice
• 1 teaspoon vanilla extract

Raspberry Swiss Meringue Buttercream

• 4 large egg whites
• 1 1/2 cups unsalted butter, cool room temperature, cut into tablespoon sized pieces
• 1/2 cup reserved raspberry jam (from above)
• Pinch of fine sea salt
• Fresh raspberries, lemon slices, freeze dried raspberries, for decorating

Instructions

1. In a medium saucepan over medium heat, cook the frozen raspberries, granulated sugar, and lemon juice until the berries release their juices and the mixture comes to a boil. Mash occasionally to break down the berries. In a small bowl, whisk together cornstarch and water to form a slurry. Stir this slurry into the boiling raspberry mixture and cook for 1-2 minutes until thickened. Push the mixture through a fine mesh strainer to remove seeds, then stir in vanilla extract. Reserve 1/2 cup of this jam for the frosting and set both jam portions aside to cool.
2. Preheat the oven to 350°F (180°C). Grease the sides of three 8-inch cake pans and line the bottoms with parchment paper. Set aside.
3. In a large bowl, rub the fresh lemon zest into the granulated sugar until fragrant. Add cake flour, fine sea salt, and baking powder, then whisk together until combined.
4. Using a mixer on low speed, mix the cubed unsalted European butter into the dry ingredients until the mixture takes on a sandy texture.
5. In a separate bowl, whisk together the eggs, heavy cream, vegetable oil, fresh lemon juice, and vanilla extract until smooth.
6. Add half of the wet mixture to the dry ingredients and mix until the flour is fully moistened. Scrape down the sides, then add the remaining wet ingredients. Pulse initially to combine, then mix on low speed until just combined. The batter will be naturally thicker.
7. Divide the batter evenly among the three prepared pans (about 485 grams each), smoothing the tops with a spatula. Bake in the preheated oven for 25 minutes or until a toothpick inserted in the center comes out with a few moist crumbs. Let the pans cool on a wire rack for 20 minutes, then remove cakes from pans and allow them to cool completely on the racks. Handle gently as layers are delicate.
8. Set a large bowl over a double boiler with simmering water. Add egg whites and granulated sugar, whisking constantly until the sugar dissolves and the mixture reaches 165°F on a thermometer.
9. Transfer the hot meringue to a stand mixer fitted with a whisk attachment. Whisk on high speed until the meringue cools to approximately 90-95°F, about 10-15 minutes, forming stiff, glossy peaks.
10. Lower mixer speed to low, then add the cooled unsalted butter pieces 1-2 tablespoons at a time, mixing well after each addition. Once all butter is incorporated, increase mixer speed to medium-high and beat until the buttercream is light and fluffy. Mix in the reserved raspberry jam and a pinch of fine sea salt until evenly combined.
11. Trim a thin layer off the top of each cake layer with a serrated knife to expose fresh crumb. Place the first layer on a serving board and spread a thin layer of buttercream to seal the crumb. Pipe a border of buttercream around the edge, then fill the center with half of the raspberry jam. Repeat with the second layer, then place the final layer upside down for a flat cake top.
12. Cover the entire cake with a thin layer of buttercream to seal crumbs, then refrigerate for 20-30 minutes until firm, helping to prevent filling from spilling out.
13. Use the remaining buttercream to frost the sides and top of the cake evenly. Use any leftover frosting to pipe decorative dollops on the top. Garnish with fresh raspberries, lemon slices, and freeze-dried raspberries as desired. Refrigerate the cake for 4-6 hours or overnight for best flavor and texture, and allow to come to room temperature before serving.

Notes

• Measure dry ingredients properly by fluffing the flour first, then spooning into measuring cups rather than scooping directly, or preferably use a kitchen scale for accuracy.
• This cake tastes best the next day, as it soaks in moisture from the filling and buttercream, resulting in a more tender texture.
• Store leftover cake slices in an airtight container in the refrigerator for up to 5 days. Let them sit at room temperature before serving for the best flavor.
• If the Swiss meringue buttercream appears thin or fails to thicken after adding butter, it might be due to warmth of the butter or meringue. Chill the bowl in the refrigerator for 15-20 minutes, then whip again until thickened.
• This recipe requires store-bought cake flour; substituting with all-purpose flour may result in a dry and crumbly texture.