As is often the way with me, I bought an exciting ingredient on a whim, used it for the one recipe I needed it for, then watched it sit in my cupboard for weeks feeling lonely and unloved. This was Yuzu. Yuzu is the most wonderful sharp, sweet Japanese citrus that is the perfect ingredient for marinades, dressings and now of course, curds. Having used yuzu for yuzu mayo in my Gua Bao recipe, I had a think about what else I like to be citrusy, and immediately thought of lemon curd. What a wonderful way to put this amazing citrus fruit to work and show off its all round wonderfulness.
I have developed this cake using eyes as well as taste buds, wanting a light flavour in the cake to compliment the yuzu curd but also a beautiful, dark colour to show off the bright yellow. As many of you may know, it’s not so easy to put fruit purée through a sponge cake and get fluffiness and even colouring. I had a few sad, flat (but delicious) purple cupcakes as a recipe test before deciding on the recipe below, with a more marbly effect, and think this one is pretty awesome. You get some berry flavour, some purply-ness, and most importantly, fluff and moisture. This is why the cake layers are quite thin as well, we’re keeping it light.
I’ve done seven layers in the photos cause I’m a weirdo and wanted a ginormous cake, but feel free to do just two layers (one cake split in two) or four layers (two cakes split in two). I’ve done the recipe for two layers, and you can repeat it to add as many on top of that as you like. I’ve even told you how to get your berries beautiful and frosty.
Notes & Tips:
For the cake: The ‘weigh the eggs’ cake method was introduced to me by my top notch baker friend. It produces a practically fail-safe, easy and delicious cake – the premise is to weigh the eggs in their shells, then use the same weight of soft butter, caster sugar and self-raising flour. Easy peasy squeeze a lemon. When you’re checking on your cake, open and close the oven door very slowly and carefully to avoid the cake collapsing.
For the yuzu curd: This is very easy to make but requires at least 4 hours chilling time in the fridge, so it’s best to make it in advance, at least the night before. If you don’t have yuzu and would like to replace with lemon curd, you can and it will be lovely, but the flavour is very different.
For the berry puree: Super easy, best to make in advance or a couple of hours before so it has time to cool.
Frosty berries: To make your berries go beautiful and frosty, take ambient berries and put them on a tray or a plate in the freezer, not piled up but on a single line, not touching each other. When ready to garnish your cake, take them out of the freezer – they will be dark and berry like, then will turn frosty and white as they hit the warm air of your kitchen, and will continue to turn frostier until they get to room temperature and start to defrost, then will then go dark again. (Pr- frozen berries will be smushed in their packaging and not as visually perfect as freezing your own berries)
Blackberry layer cake with yuzu curd
Quantities: 1 x 6″ cake with 2 layers. Double the recipe as necessary, 1 cake = 2 layers.
Kitchen stuff: baking paper, hand whizzer or food processor, palette knife, piping bag, 6″ / 15cm cake tin(s) – if you would like two layers, you will need 1 cake tin, if you would like 4 layers, you will need 2 cake tins etc., unless you are happy to do one cake after another (like me) which is more time consuming!
Timings: Yuzu curd: 15 minutes (hands on), Berry puree: 15 minutes (very hands off), Per cake: 15 minutes mixing, 30 minutes baking and 35 minutes cooling, Buttercream: 15 minutes, Cake assembly: 20 minutes – if you do the puree and curd in advance, leave around 2 hours for the cake.
Yuzu curd (makes one jar)
80ml (1/4 cup + 1 tbsp) yuzu juice, such as this one
200g (1 cup) granulated sugar
1 large egg
3 large egg yolks
2 tbsp lemon juice (about 2 lemons worth)
100g (7 tbsp) lightly salted butter
50g frozen blackberries (or Black Forest berries)
50g frozen blueberries
MAKES ONE 6 INCH CAKE
2 large eggs, weighed in their shells
The same weight of very soft butter (leave it out over night or a few seconds in the microwave)
The same weight of caster sugar
The same weight of self-raising flour, I use Shipton Mill
Generous pinch of salt
1 tsp baking powder
¼ tsp baking soda
3 tbsp home made berry puree
Blackberries and blueberries, for decoration – freeze in advance for a frosty look, see notes & tips above.
For the Buttercream (enough for a 7 layer cake)
200g soft butter
350g icing sugar
2 tbsp whole milk
3 tsp yuzu
Yuzu curd method:
In a saucepan, whisk together the yuzu juice, lemon juice, egg, egg yolks and sugar. Cut your butter into cubes and put it in a medium heatproof bowl, set aside. Heat the egg/yuzu mixture slowly on a medium heat, stirring continuously to avoid scrambled eggs, until the yuzu is thick enough to coat the back of the spoon and you can see glimpses of the bottom of the pan as you stir. You want the temperature to be above 70C (160F) . Immediately pour the hot, thick yuzu mixture over the butter and keep stirring until it’s all melted and mixed together. Cover with cling film, with the cling film touching the surface of the curd to avoid a skin forming and move to the fridge. Chill for 4 hours or overnight until set.
Berry purée method:
Heat the berries in a saucepan on medium heat with a splash of water. Keep heating & stirring occasionally as the berries slowly melt and turn soft – there will be lots of liquid. After 10-15 minutes, remove the saucepan from the heat and use your hand whizzer in the saucepan to purée the berries until smooth. You can run this though a sieve if you wish for a very smooth purée, or leave as it is. Allow to cool then remove to a jar and keep in the fridge. Any leftovers are amazing on porridge.
*This is the recipe for one 6 inch cake (one cake = two layers). If you are baking multiple cakes at once, double or triple the recipe as necessary, depending on how many layers you would like to do. I had one cake tin and repeated this cake recipe, making one cake at a time, rather than making a large batch of mixture.*
1. BUTTER & SUGAR: Freeze your berries for decoration (see notes & tips above). Preheat the oven to 180C (350F) then grease and line your 6 inch cake tin base with baking paper. Use a hand mixer (or a stand mixer) to mix the butter and the sugar in a medium bowl until very light and fluffy, this should take a couple of minutes. Make sure to scrape the sides down and make sure it’s all mixed in together.
2. EGGS & FLOUR: Beat the eggs together in a little bowl, then add to the butter and sugar, a little at a time, whilst continuously mixing. Keep scraping the side of the bowl down to make sure it’s all properly combined. Add the self-raising flour, baking powder, baking soda and salt then gently fold it in to the mixture.
3. BERRIES & BAKE: Split the mixture in two, and add a 1½ tbsp berry puree to each half. Gently fold in the berry puree until roughly distributed but still marbled, you don’t want it fully mixed (as pic below). Scrape both halves of mixture into your prepared cake tin and smooth the top with a palette knife. Bake in the centre of the hot oven for 25 – 30 minutes, until an inserted skewer comes out clean, and the cake is golden brown (from what you can see!)
4. HALVE IT: When the cake is ready, leave it to cool in it’s tin for a few minutes, then remove the tin and cool the cake on a wire rack. After about 15 minutes, move the cake to the fridge, and continue to cool for a further 15/20 minutes or so. Make the buttercream whilst the cake is cooling, then cover with clingfilm and set aside. Once the cake is completely cool, remove it from the fridge. Using a sharp, serrated knife, gently and slowly slice the cake in half widthways, being careful to line up the sides so you have an even surface on each side. It may be worth scoring a guide line around the cake before slicing. Move your two halves aside gently, and continue on any other cakes you may have baked!
5. ASSEMBLE!: When you’re ready to assemble your cake, have all your ingredients ready. You want a piping bag ready with some buttercream in it, a sturdy board on which to place your cake, the cakes all halved and your yuzu curd accessible with a tablespoon. It’s a good idea to practice assembling your cake tower with just the cake halves first, so you can see which layers work well on top of each other, it’s best to use a very flat, even slice for the top and the bottom layers.
Start with a layer of cake on your board, and cover it in a medium-thick layer of yuzu curd, leaving a slight gap at the outer edge of the cake. The less layers you are doing overall, the more yuzu curd you can put on each layer. Then pipe a ring of buttercream around the outer edge of the cake, this supports the upper later of the cake and also keeps the yuzu curd from spilling out. Repeat until you reach the top layer. Smother the outside of the cake in buttercream blobs. Using a palette knife, spread the buttercream over the cake until you have an even covering. I went for the ‘naked’ look, but feel free to cover the cake entirely.
Buttercream Method *make whilst cake is cooling*
1. BUTTER & SUGAR: In a large mixing bowl, using a hand mixer or a stand mixer, beat the butter until very light and fluffy. Add a third of the icing sugar, and gently mix together with a spoon before using the mixer (this is to avoid getting engulfed by an icing sugar cloud, as I did). When lightly mixed, beat thoroughly with the mixer and repeat with the remaining two thirds of icing sugar. At this point, taste the buttercream, if you would like to add more icing sugar, please do so!
2. YUZU & MILK: Add your yuzu juice, one tsp at a time, mixing well after each addition. When combined, add the milk, 1 tbsp and continue to beat until all mixed together. If you feel it needs more milk, add the second tbsp of milk and repeat, otherwise you’re good to go. You should then have a beautiful, light and fluffy butter cream that tastes wonderful, with just a hint of yuzu flavour.