Rhubarb and Custard Viennese Whirls

With all this unfeasibly cold and snowy weather, I’ve not only gone baking crazy – I’ve gone viennese whirl crazy. Not content with making one or two batches of viennese whirls, I’ve made at least eight. Each batch just had something slightly wrong that I wanted to improve on. So I just made more, and more and more. Oh the shame.

Observations after making hundreds of viennese whirls:

  1. The butter needs to be practically melted if you are to have a hope in heaven of piping anything out
  2. Guernsey butter produces a flipping lovely viennese whirl
  3. Otherwise, don’t forget to add a pinch of salt to unsalted butter and that all-important vanilla extract
  4. Don’t overmix your biscuit dough or it has a tendency to spread in the oven. However, mix it well enough that it doesn’t fall apart into a handful of crumbs.
  5. Resting the piped dough in a cool place for around 30 minutes before baking is an excellent way to ensure they keep their shape
  6.  Leave the biscuits to chill out for a few hours before trying to sandwich them or they break up into a sad mess

Most of these viennese whirls were wonderfully classic vanilla buttercream and jam affairs, which I’ve posted about before but I’d also recently made some roasted rhubarb and custard yo-yos from Ottolenghi’s Sweet and fancied doing a little riff on that (and also had a surplus of rhubarb puree, more on that later).

To do this, I took my usual recipe, replaced the cornflour with custard powder, and threw in a bit of extra vanilla extract. With the buttercream, I added in a little roasted rhubarb puree and a splash of lemon juice instead of vanilla extract.

Now the original buttercream from Ottolenghi’s Sweet was frustratingly difficult to get right. The recipe seems to be based on something that would have been practical if it had made 5 times the quantity of biscuits, but had been scaled down for the home cook. For instance, it asks you to roast the tinest amount of fresh rhubarb, then blend it into a puree. Practically, this didn’t work as my stick blender couldn’t cope with the tiny quantity. So, I ended up roasting several sticks of rhubarb and making a larger batch of puree instead.


It’s quite hard to get a good balance of rhubarb flavour, and good textural consistency for the buttercream itself. Add too much rhubarb puree, and the icing curdles, but don’t add enough and the flavour just isn’t really there.

I was a bit impatient after baking these, and in my hastiness to sandwich them, they were still a bit too delicate and started to crumble around the edges. I don’t think they turned out too badly though!


Next time as well as leaving the biscuits for a bit longer to firm up, I’d consider upping the rhubarb flavour by adding a small dollop of fresh rhubarb compote before sandwiching the biscuits. Even though I love a good classic, I think this new combination has the promise to be just as delightful, with the tartness from the rhubarb and lemon juice adding an extra dimension to the original buttery sweetness. Do give it a whirl!

Rhubarb and Custard Viennese Whirls

Makes 6-8 whirls

For the biscuits:

  • 125g salted butter
  • 125g plain flour
  • 25g icing sugar
  • 25g custard powder

For the buttercream:

  • 60g unsalted butter
  • 120g icing sugar
  • 1/2 tsp lemon juice
  • 1 tbsp roasted rhubarb puree

Make the roasted rhubarb puree first by cutting fresh rhubarb into chunks, then spreading out onto a baking tray, and roast in the oven at 180˚C for around 20 minutes til soft. Leave to cool then blitz into a puree.

Make the biscuits. Soften the butter til almost melted. Sift together the dry ingredients, then gradually beat them into the softened butter to form a soft dough. Transfer to a piping bag with a star-shaped nozzle, and pipe whirls onto a baking tray. Leave to sit for around 30 minutes.

Heat the oven to 170˚C. Bake the biscuits for around 20 minutes or until golden on the edges. At this point, I went out into the garden and made a very tiny snowman. A has named it Steve.

Leave biscuits to cool.

Make the buttercream by beating the butter and icing sugar together until fluffy, then adding the lemon juice, and a little rhubarb puree until it is pink and fluffy. Transfer into a piping bag, and pipe a circle of buttercream onto one biscuits, then sandwich with another. Repeat with the other biscuits.


5 thoughts on “Rhubarb and Custard Viennese Whirls

  1. They look so beautiful, Ella! Very defined, pretty whirls. I also love the idea of adding a bit of compote in the middle for an extra flavour punch. The last time I made viennese whirls they spread in the oven, despite pre-chilling them in the fridge before hand. I was gutted as I had busted out my Hulk muscles to get them piped in the first place so it felt like a total waste of energy, haha. Still tasty though!

    Also, thank you so much for your comment on my last post. I think what you said was bang on. Most baking blogs at the moment seem very glossy/professional, which although beautiful can feel a bit impersonal or just too staged. I also miss the diary-like, “take a quick snap” approach.to blogging, so I’ve decided not to get too hung up on photography. If it’s just a quick snap with my phone, then that’s ok. For me, blogging is about sharing my interests and engaging with other like-minded bloggers, not about creating the most pinterest worthy image.


    1. I feel you, it’s so annoying when you put in the effort and they just don’t turn out how you want them to! I burst around 6 piping bags during my 8 batch adventures along the way so certainly no shortage of baking casualties along the way. I completely agree with the way you feel about how blogging has changed, and pretty sure that’s what made me more disengaged and disillusioned along the way, but so pleased to see you are going for the return to old-school blogging too! I am looking forward to more dinosaurs and booby biscuits 😀


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