It was my brother’s birthday a couple of weekends ago and rather than make a cake I’ve made before, I thought I’d try something new. My mother, as per usual, asked if that was wise and once again I answered with, ‘Maybe not wise, but definitely more interesting!’.
This divine looking cake came straight out of Yotam Ottolenghi’s equally divine book, Sweet, 2017. And, by the way, if you haven’t secured yourself a copy of this book, you really must! It’s jam-packed full of mouth-watering baking and desserts that you’re most definitely going to want to try.
The recipe itself was actually for a Lemon & Blackcurrant cake, but as blackcurrants are not readily accessible, I opted for a raspberry version instead. And, holy-moly, what a little stunner it turned out to be!
The crowning glory for this cake is its exceptionally light and silky French buttercream, made by adding hot sugar syrup into beaten egg yolks, after which butter is gradually beaten in. With the addition of tangy raspberry puree, it really is heavenly and absolutely the best buttercream I’ve ever tasted! Okay, it’s a bit tricky to make and I have to admit to having had a ‘fail’ before I nailed it, but I learned a lot and have added some extra notes about the process in the recipe which should make it easier.
The lovely surprise of this cake, for guests at least, is that it is a vertical stripe cake. You might think it’s difficult to make one, but it’s really not. It’s basically a sheet cake cut into three narrow lengths, each covered in buttercream and then rolled (one after the other) into a spiral formation, which is then turned on its side and covered with the remaining buttercream.
I’ve made a vertical stripe cake before and have quite a few process photos from that bake if you’d like to see how it’s achieved. The process felt a lot easier this time around – I think the biscuit sponge was more pliable and easier to roll than the genoise sponge I used previously (if you look at my process photos for that cake, you’ll see how challenging it was!).
You might be surprised by how small a cake this is – I was actually a little shocked myself. I guess I’m used to a cake serving 12-15 slices. This one, in comparison, served only 8 decent sized slices (10 at a stretch), which was perfect for our family group of seven (the birthday boy got an extra slice!). So, just be warned and don’t make this for a big dinner party!
If, however, you have a modest gathering and want to serve something outrageously delicious, not overly sweet, and comparatively light on the stomach, this show-stopper cake will most certainly fit the bill. Enjoy!
RASPBERRY & LEMON VERTICAL LAYER CAKE
For the cake:
- 8 large eggs, whites and yolks separated
- 4.9 oz caster (superfine) sugar, plus an extra 0.7 oz
- 1 tbsp lemon juice
- 2.8 oz plain flour
- 1/8 tsp salt
- Finely grated zest of 1 small lemon
- Icing sugar (confectioner's sugar), for dusting
For the raspberry puree:
- 10.5 oz raspberries, fresh or frozen and defrosted
- Optional: 1.4 oz extra raspberries to garnish
- 2.1 oz caster (superfine) sugar
For the raspberry buttercream:
- 2.9 oz golden syrup or corn syrup
- 4.2 oz caster sugar
- Scraped seeds of 1/2 vanilla pod
- 4 large egg yolks
- 10.5 oz unsalted butter, cut into 3cm cubes, softened
- 3.5 oz raspberry purée (see above)
For the cake:
- Preheat the oven to 200°C (390°F). Line a 40 x 32cm (15.7 x 12.5 inch)* baking tray with baking paper.
- Place the egg yolks in the bowl of an electric mixer with whisk attachment. Add 140g (4.9 oz) sugar and the lemon juice and beat on a medium-high speed for about 3 minutes, until pale and thick.
- Transfer the mixture to a large below. Sift the flour and salt directly over the egg mixture in two batches, folding through the mix with a spatula after each addition. Sprinkle the lemon zest on top and set aside.
- Place the egg whites in a clean bowl. Using either your electric mixer, or a hand mixer, whisk on a medium-high speed until soft peaks form, then slowly add in the extra 20g (0.7 oz) sugar, continuing to whisk until firm peaks form.
- Gently fold a third of the egg whites into the egg yolk mixture until incorporated. Finally, fold in the remaining egg whites until combined, then scrape the mixture into the baking tray. Even the top out with a small spatula.
- Bake for 15 minutes, or until the sponge is a light golden brown and a toothpick inserted into the centre comes out clean.
- Remove from the oven and place on a wire rack to cool in the tray for 5 minutes before dusting the top lightly with icing sugar. Place a clean tea towel on top of the sponge, then flip it over so that the sponge is now lying on top of the tea towel. Carefully peel away the paper and trim the very edges of the sponge, if they need straightening.
- Starting at the short edge of the sponge, carefully roll it up along with the tea towel – this will ensure the cake will roll without cracking later. After about 20 minutes, or when the sponge is no longer warm, unroll the sponge.
- With the short end facing towards you, measure and cut three equal strips parallel to the long edge (a pizza cutter is useful here). Cover with a clean tea towel and set aside.
For the raspberry puree:
- Place the raspberries and sugar in a medium saucepan and place over a medium-low heat. Warm through for 4–5 minutes, until the raspberries have softened and the sugar has dissolved. Transfer to a food processor and process to form a purée. Strain through a fine sieve set over a bowl to catch the purée: you need 150g (5.2 oz) only.
For the raspberry buttercream:
- Place the golden syrup, caster sugar and vanilla seeds in a medium saucepan. Place over a low heat and stir until all the sugar dissolves.
- At the same time as you start making the sugar syrup, place the egg yolks in the bowl of an electric mixer with whisk and beat on a medium-high speed until thick and pale lemon in colour.
- Check the syrup – when all the sugar has melted, increase the heat to medium and simmer until bubbles begin to appear. Continue to simmer until there are large bubbles all over the surface of the syrup – if you have a thermometer, you want to reach 238F (114C). Remove the pan from the heat and carefully pour the hot syrup in a slow, steady stream down the edge of the mixing bowl into the beating yolks (be careful that the syrup doesn’t hit the whisk, or it will splatter around the bowl and harden almost immediately). When all the syrup has been added, increase the mixer speed to high and continue to whisk the mixture for about 10 minutes, until the outside of the bowl is no longer warm.
- Gradually add the butter, one cube at a time, allowing it to be incorporated into the mix before adding the next. When all the butter has been added, scrape down the bowl and continue to whisk for another minute, until the buttercream is very smooth and light. Gradually add 100g (3.5 oz) raspberry purée and mix on a medium speed until fully incorporated.
To assemble the cake:
- Spread each of the strips of sponge with about 80g (2.8 oz) raspberry buttercream: this should leave you with about 300g (10.5 oz) to ice the top and sides of the cake later. Take one strip of sponge and, starting with the short end, roll it up. Once this strip is rolled, position the exposed end at the beginning of the next strip and keep rolling. Repeat with the finalt strip and continue to roll until the entire cake is rolled into a spiral shape. Turn the cake on to a serving plate so that it is standing on one of its flat ends.
- Spread the remaining buttercream all over the top and sides of the cake, smoothing with a spatula to create an even surface.**
- Drizzle the remaining 50g (1.7 oz) raspberry purée on top of the cake and top this with the raspberries reserved for garnish.*** Set aside for at least 1 hour at room temperature (or in the fridge if it is a very warm day) before serving.