Vertical cake with lemon sponge and raspberry buttercream

Ingredients:

Sponge cake

• Unsalted butter for greasing the baking sheet
• 3/4 cup heavy cream
• 1 cup (130 g) premium flour
• 0.5 tsp baking powder
• 0.5 tsp salt
• 7 large eggs (separate the yolks from the whites) + 3 large yolks
• 1 tsp vanilla extract
• 1 tbsp lemon extract
• Zest of 2 lemons
• 1 teaspoon distilled white vinegar
• 3/4 cup (150 g) granulated sugar

Butter cream

• 340 g frozen raspberries
• 3 tbsp. granulated sugar
• Juice of half a lemon
• 8 cups powdered sugar
• 0.5 cup + 2 tablespoons pasteurized egg whites
• 1 tbsp vanilla extract
• 700 g softened unsalted butter
• 1 tbsp. l. orange liqueur

Decoration

• Freeze-dried raspberries, crushed, for sprinkling
• Special equipment: pastry bag with a small fluted tip

Preparation:

1. Biscuit:

   
   Preheat oven to 200°C. Grease the bottom of a 45x32 cm baking pan and line the bottom with parchment paper. Grease the parchment paper.
2. Microwave the cream until steaming, about 1 minute. Transfer to a stand mixer and combine with the flour, baking powder, and salt. Beat until smooth. Add 10 egg yolks, vanilla extract, lemon extract, and lemon zest, beating until completely smooth. Set aside.
3. In the bowl of a stand mixer fitted with the whisk attachment, beat the egg whites on medium speed until foamy, 1–2 minutes. Add the vinegar and slowly add the granulated sugar over 30 seconds. Then increase the mixer speed to medium-high and beat until medium peaks form, about 2 minutes.
4. Using a spatula, fold the beaten egg whites into the batter in three additions. Do this carefully to ensure the batter is airy. Pour the batter into the prepared pan and smooth the surface.
5. Bake until golden and springy, 14–16 minutes. Let cool on the baking sheet for 5 minutes. Run a spatula around the edges of the cake, cover the cake with a sheet of parchment paper, place a wire rack on top, and invert the cake, removing it from the pan. Invert the cake and let it cool.

6. Butter cream:

   
   In a large, heavy-bottomed saucepan, combine the raspberries, granulated sugar, lemon juice, and 2 tablespoons of water and bring to a boil over medium heat. Crush the raspberries with a spoon. Continue cooking, stirring frequently, until the liquid has reduced by about half, 10–15 minutes. Strain through a sieve and let cool (but do not refrigerate).
7. In the bowl of a stand mixer fitted with the whisk attachment, combine the powdered sugar, egg whites, and vanilla. Mix on low speed until the sugar is incorporated, then increase the speed to high and beat for 10 minutes. Add half of the softened butter, beating until smooth. Add the remaining butter, scraping down the sides of the bowl and whisk, then continue beating at medium speed until fluffy and smooth, 2–3 minutes. Add the cooled raspberry sauce. Add the orange liqueur. Increase the mixer speed to medium-high and beat until smooth.

8. Assembly:

   
   Cut the cooled cake into three equal, 10 cm wide pieces, lengthwise. Spread about 1 cup of raspberry cream on each strip. Roll the first strip into a log, then bring the end of the first log to the beginning of the second strip and continue rolling. Add the third strip in the same way. Turn the cake upside down and place it on a cake stand.
9. Cover the cake with raspberry buttercream. Transfer the remaining buttercream to a pastry bag fitted with a small fluted tip. Pipe the buttercream onto the surface of the cake and sprinkle with crushed freeze-dried raspberries.