Yuzu – its becoming a gourmet buzzword, stretching out from its Japanese “homeland” (it originated in China but was introduced into Japan about 600-900AD) into Japanese – fusion and not even fusion restaurant fare. It’s an iconic citrus in Japanese cuisine, to me being a cross between a lime and a grapefruit in flavour.

I came across it by culinary adventurism – in Takayama, Japan. I’d seen a picture of it in a Japanese guide book and thought it was interesting, but whilst sitting at in a Takayama restaurant eating a delicious bowl of sweet soy stewed Hida beef and rice, I spied a bottle of shochu on the bar which had a picture of a yellow fruit on it. I pressed my travel companion and Japanese speaker Francie to ask what it was. “Yuzushu” was the answer. Yuzu flavoured shochu.

Yuzushu and Umeshu (known to us Gaijins as “plum wine”)

I know an opportunity when I see one. I ordered a Yuzushu on the rocks, and entered into a new realm of foodie heaven. I ordered another. And spent the rest of the trip hunting it down so I could take some home.

Since then, Yuzu has been popping up in trendy food all around Australia. And I can smile smugly to myself, because I knew it before it was “famous”.

Yuzu is often used as a flavouring in savoury dishes but it is superlative as a replacement in citrussy desserts. I love to use it in lemon meringue pie – Yuzu meringue pie, and watch people wonder at the flavour they are experiencing. How do you do it? they ask.

By knowing stuff, I respond. Heh heh heh.

However, too good not to share. It’s hard to buy Yuzu fruit in Australia – its seasonal and there is only one website I have found from which you can get it – and I confess despite further searching in Japan I have never seen one in the flesh – but luckily the Japanese are masters at food products, and you can buy Yuzu juice in little bottles in good Asian food stores.

From Yuzu meringue, it’s a short step to realising Yuzu curd is a great idea. And if a lemon curd cake is stupendous, then a Yuzu curd cake will be better. And just as I was surmising all of these matters, along came an excuse to put my theories to the test.

My birthday.

Being somewhat “Monica from Friends” in the kitchen, I am well known for making my own birthday cake. If you want something done right, do it yourself. I do not care about the fact I had to work for my birthday – I always get the best cake on Earth.

Like this one.

Meet the Yuzu Gateau.

Yuzu syrup soaked vanilla Victoria sponge, Yuzu curd with vanilla buttercream, and Yuzu mousseline frosting.

Mousseline is the wealthy cousin of butter roux frosting. It’s made with crème patissiere instead of white roux, and is just the creamiest, lightest buttercream of them all. My Yuzu Mousseline has the base crème patissiere made with a combination of milk and yuzu juice, and it is simply divine.

This cake was also a chance to try out silver leafing and a formal cake with piped rosette decorations. Oh and a little meandering garden of handmade sugar flowers. You know, because I can. And now you can too.

Yuzu Gateau

Yuzu Birthday Gateau

Makes a double barrelled 15cm cake, enough to serve approximately 40 people.

Note that the yuzu mousseline is very temperature sensitive, so make sure this cake is not left out of the refrigerator for more than two hours at a time (less if the day is very hot!).

basics

two 15cm round cake cards (from cake speciality shops or good cooking shops)
four wooden cake dowels (from cake speciality shops or good cooking shops)
two 15 cm round, 7 cm high vanilla Victoria Sponges (made with a total of 8 eggs)
Yuzu Syrup (recipe below)
300 g vanilla buttercream
Yuzu Curd (recipe below)
Yuzu Mousseline (recipe below)
10 sheets of edible silver leaf (optional)
A little leaf green gel food colouring
Assorted sugar flowers (you can purchase these from specialist cake shops if you have never made them before – one day I might blog about them, but in the meantime, get a copy of Peggy Porschen’s book Cake Chic for a lesson (in all types of cake decorating) from the master! I tend to always have a few flowers kicking around that I have made earlier – they keep pretty much forever)
Coloured cachous, if desired

recipes

Yuzu Syrup

50 mL water
50 g caster sugar
30 mL Yuzushu (or Yuzu juice, but I really recommend you find and own some Yuzushu)

Combine water and sugar in a small saucepan, bring to boil swirling to dissolve, boil 1 minute. Stir in Yuzushu when cool.

Yuzu Curd

100g sugar
70g unsalted butter
1 egg
1/4 cup yuzu juice

Combine butter and sugar in a small saucepan and heat over a low to medium heat, stirring continuously, until the butter is melted and sugar starts to dissolve (its hard to make it dissolve completely). Lower heat. Cook gently, stirring constantly until the mixture starts to thicken to the consistency of runny honey. Do not let the mixture boil or it will curdle. Set aside the mixture and let cool. Refrigerate until needed.

Yuzu Mousseline

2 large egg yolks
1 large egg
25g cornflour
25g custard powder
130g sugar
350mL milk
125mL yuzu juice
200g unsalted butter, cut into pieces

Combine the egg yolks, egg, cornflour, custard powder and half the sugar in a mixing bowl and whisk until well combined and lightened in colour. Whisk in the yuzu juice. Heat the milk until nearly scalding.

Whisking the egg mixture constantly, pour the hit milk over in a thin stream. Return the mixture to the pan, and heat, stirring constantly with the whisk until the mixture boils. Let the mixture bubble, stirring constantly for about two minutes, until the creme patissiere is thick and smooth.

Remove the pan from the heat, pour the creme patissiere into a shallow pan and let cool to blood temperature.

Beat the creme patissiere until it is blood temperature. Beat in the butter, a cube at a time until it is all incorporated and the mousseline is very light and fluffy. Scrape the sides of the bowl down with a rubber spatula from time to time during this process. Tint the mousseline a very pale green if desired.

Use the mousseline immediately.

assembling the cake

Trim the cakes to an even height, they should be about 7 cm. Split each cake in half, then each half into half, yielding four layers. Working one cake at a time, place your bottom layer of cake onto a cake card and lightly brush the top of this layer with Yuzu Syrup (about a tablespoon). Next, spread a 3mm coat of vanilla buttercream on the layer. On top of this, spread about 2-3 tablespoons of Yuzu Curd. Place a second layer of cake on top and repeat until the fourth layer has been put on the cake. Don’t buttercream the top of this one yet – set the cake aside and repeat the process with the other cake. Chill the layered cakes until the buttercream is very firm and the cakes are cold.

Remove the cakes from the fridge one at a time, and using half of the remaining buttercream for each cake, make a light but even coating on the top and sides of the cake. Return the cakes to the fridge and chill again.

Stack the cakes one upon the other: you will need to insert four dowels into the bottom tier of the cake, evenly spaced in a four point pattern with each point located about 3cm from the outer edge of the cake, as you can see in the photo below.

Bottom tier with dowels in place

Trim the dowels to exactly the same height as the bottom tier by pushing them into the cake, marking the top of the cake on the dowel with a pencil, and cutting the dowel with a sharp knife (I like to do this by sawing the dowel with my serrated bread knife!). Check that the dowels are all the same length, otherwise this will cause the top cake to sit at an angle instead of straight! Pop the top tier on top of the bottom tier and check carefully that the double barrelled cake is the same height all around and that the sides look straight all the way up. Adjust if necessary by inserting or removing a little buttercream between the tiers. Return the tiers to the fridge until ready to do the mousseline coat – or you could make the mousseline while you are chilling the layers.

yuzu mousseline coat

Top tier coated with Yuzu Mousseline

Remove the top tier of the cake only from the fridge. This will be coated with a smooth coat of mousseline, then silver leaf. The bottom tier will have rosettes piped directly onto the buttercream coat.

Using a long offset palette knife, carefully spread a layer of the mousseline (about 4mm deep) on the sides and top of the cake, rotating the cake as you go. You will use about half of the mousseline in this step. Smooth the top ensuring as level a surface as possible. Make sure that your apparently flat surface isn’t higher on one side of the cake than the other – its very hard to disguise slight lopsidedness. You might want to return the frosted cake to the refrigerator to harden, then, using a hot palette knife (heat it in very hot water, then dry thoroughly before use), smooth any small ridges away. Place the cake in a airtight container (for protection, and to stop the mousseline taking on any “fridge smell”) and return the cake to the refrigerator until you get up the courage to do the silver leaf.

silver leafing

Coating the tier with silver leaf

rosettes and final decorations

It turns out that piped rosettes are really quick and easy to do and the effect is just stunning. Definitely a technique to add to your arsenal.

Position the top tier of the cake on the bottom tier. Because the top tier is already frosted, it will overhang the lower tier slightly. Load the rest of the mousseline into a large piping bag fitted with a flower tip (this tip looks similar to a star tip but the inner points of the star come almost into the centre, and the outer parts of the star are slightly gaping. I use a Wilton 2D). Start with the big rosettes first. Pipe the rosettes, starting in the centre of the “flower” and moving outwards in a spiral, letting each widening circle slightly overlap the previous round. You can make your rosettes as big or small as you like – I have made the large rosettes on my cake about 5cm in diameter. Fill in the gaps in the cake with smaller rosettes or small star type flowers (made by piping the mousseline straight onto the cake without moving the piping bag). Allow just a few of the rosettes and little star flowers to come up onto the lower part of the top tier.

Piping rosettes on the bottom tier

Finally, place sugar flowers onto the cake, focussing on making a wavy garland around the join between the top and bottom tier of the cake. Let the flowers drift above and below occasionally, fixing them to the top tier with a little blob of mousseline.

Dot the piped rosettes here and there with pink, green and silver cachous.

Adding flowers

There it is. One super pretty, superbly delicious birthday cake! Happy birthday to meeeeee!

I hope you try this cake out sometime – or at least some of the techniques!
Enjoy!xxx