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Week 5 on Bake Off 2021 was German Week, and this week’s Prinzregententorte Technical Challenge really was a challenge! 8 thin layers of sponge, a complex German chocolate custard buttercream, finished with a chocolate ganache and piped chocolate crowns – it took forever XD!
I am half German, but I had never heard of this cake before! I recognised it when I saw it, but I had never heard of it referred to as Prinzregententorte, or Prince Regent Cake as it would translate to literally. According to Wikipedia it is a Bavarian cake named after Luitpold, who was Prince Regent of Bavaria back in 1886. The cake is meant to have 6 or 7 layers, whereas Prue’s has 8, and Wikipedia says it sometimes also has some apricot jam added to the topmost layer. I actually think adding some apricot jam into chocolate sandwich cakes is a pro-tip (I do it for my Ultimate Chocolate Fudge Cake), so perhaps you could try that if you give this cake a go!
The four components of the Prinzregententorte
The Sponge
Prue’s interpretation of the Prinzregententorte is made with 8 individual thin layers of sponge! It has a very light, almost pancake-like texture as they puff up whilst baking in the oven. The sponge is made my folding a meringue into whisked egg yolks and sugar, before adding flour, bicarbonate of soda and melted butter. I don’t know what you’d call this kind of sponge – a mix of a genoise, chiffon and whisked sponge? No clue! It tasted good though 😊!
The recipe calls for using Vanilla sugar, which is a very popular ingredient in German baking. I have some that I brought from Germany, but you can also by it online here. You could also just use a bit more additional caster sugar though if you don’t want to buy it especially.
The trickiest thing when making this sponge is dividing it evenly to make 8 equal sponges. I find this easiest to do by weighing the baking bowl while it is empty, and then working out the weight of the mix by deducting the weight of the bowl at the end. Dividing that amount by 8, I worked out that each of my individual layers would have around 120g of batter. If your oven is big enough, you can maybe bake three sponges at a time, bearing in mind that the ones further down might need slightly longer to bake than the top ones if they are getting less heat. It’s a bit of a balancing act, but doable 😉!
German Chocolate Buttercream
The chocolate buttercream in this recipe is quite a classic German buttercream. In Germany, people like to add custard to buttercream to give it a richer (often vanilla) flavour. And this recipe does exactly that, except that you are adding a chocolate custard to the buttercream, and enriching it with additional melted dark chocolate! It tasted delicious!
The custard is made like any other custard, but contains a bit more cornflour to help thicken it. You can read more tips about making a good custard in my Baking Basics post here.
Chocolate Ganache
Once the individual sponge layers have been sandwiched with the chocolate buttercream, the cake is covered in a smooth and rich dark chocolate ganache! I love chocolate ganache, it’s just so rich and delicious! Ganache is very easy to make, all you need is some dark chocolate and double cream! The cream is warmed until just below boiling point, and then poured over the chocolate to melt it. Make sure to chop the chocolate quite finely to help it melt and then put it into a heat-proof bowl. I find covering the bowl with a plate once you have poured over the cream helps keep the heat in, and then just leave it to stand for 2-3 minutes! Once you then stir the mix, it will come together into a beautifully shiny chocolate ganache! This recipe also calls for adding a little butter at the end, which adds to the richness of the ganache, and the extra fat content ensures that the ganache doesn’t set rock-hard.
Mini Chocolate Crowns with Gold Glitter
If you want to go the extra mile and make the Prinzregententorte exactly as on Bake Off, you will also need to make 12 small chocolate crown decorations for the top of the cake. I have created a template for this which you can find below and print out 😊. Once piped, scatter over the gold glitter or if you are using a spray, wait until the chocolate has hardened before spraying it on.
Equipment needed for the Prinzregententorte
This cake is very difficult to make if you don’t have the right equipment. First of all, you will need an electric hand-held or free-standing mixer (I was luckily able to use my Kenwood), because there is no way you will manage to get the meringue or egg yolks as whipped as you need them to be if you do them by hand!
Prue’s recipe said to make the sponge circles 25cm in diameter and then trim them to 23 after baking. To me, that seemed like a waste of sponge and would surely result in thinner layers and a flatter cake. So I opted for 24cm instead, and thought that was a good idea! Not only did I hardly need to trim the sponges, but I also got a good height on the individual sponges and the final cake! So I’d recommend doing that, too.
Prue’s recipe also says to assemble the cake in a deep 23cm loose-based tin. Whilst you can do that, I don’t actually own one. Instead, I used something else which is far more popular in Germany to use when decorating cakes (or “Torten” as they are called) like this. And that is an adjustable cake ring, that you can just tighten around the cake and adjust to any size you like. This is not the exact one I have, but shows what I mean and might be even better as it has a proper clip to maintain the size. To stabilse the base of the cake, I just placed it onto a cake board and set that onto a cake lifter (I used Mary Berry’s from Lakeland).
Finally, you will also need 3 baking trays (ideally), two piping bags, a star-shaped nozzle, spatulas, wire cooling racks, a small palette knife and LOADS of baking paper! So this cake is definitely equipment-heavy!
More Bake Off Technical Challenges
I am absolutely obsessed with the Great British Bake Off and have challenged myself to attempt all of (or at least the ones that are “realistic” – I won’t be making pitta breads on a camp fire in the back garden!) the technical challenges from the programme! I have tried quite a few already, so make sure you check out some of the other recipes and see how I got on!
- Mary Berry’s Religieuses
- Mary Berry’s Fraisier Cake
- Paul Hollywood’s Hand-raised Chicken, Bacon and Apricot Pies
- Mary Berry’s Bakewell Tart with feathered Icing
- Paul’s Mini Pineapple Upside Down Cakes
- Mary Berry’s Frosted Walnut Layer Cake
- Paul Hollywood’s Cottage Loaf
- Mary Berry’s Homemade Jaffa Cakes
- Paul Hollywood’s Wagon Wheel Biscuits
- Mary Berry’s Victoria Sponge Cake
- Paul Hollywood’s Mini Pork Pies
- Mary Berry’s Viennese Whirls
- Prue’s Vegan Chocolate and Raspberry Tarts (S2UC Special)
- Pizza Star Bread (Junior Bake Off)
- Mary Berry’s Coffee and Walnut Battenberg Cake
- Paul’s Crusty White Cob
- Paul Hollywood’s Rainbow Bagels
- Prue Leith’s Malt Loaf
- Paul’s Jammy Biscuits
- Paul Hollywood’s Olive Ciabatta Bread Sticks with Homemade Tzatziki
- Prue Leith’s Sticky Toffee Puddings with Sesame Tuiles
- Prue Leith’s Prinzregententorte
- Paul Hollywood’s Baklava (22cm)
- Paul’s Caramel Biscuit Bars (Twix)
- Prue Leith’s Vegan Sausage Rolls
- Prue’s Sablé Breton Cake
- Paul Hollywood’s Sticky Belgian Buns
- Red Velvet Cake with Cream Cheese Icing
- Prue’s Garibaldi Biscuits with Feathered Chocolate Icing
- Paul Hollywood’s Pain au Raisins
- Paul’s Spicy Beef Tacos
- Paul Hollywood’s S’mores
- Prue Leith’s Pistachio Praline Ice Cream Cones
- Vegetable Spring Rolls
- Prue’s Vertical Chocolate, Hazelnut, and Raspberry Tarts
- Paul Hollywood’s Devonshire Splits
Prue Leith’s Prinzregententorte | Bake Off Technical Challenge
Recipe
Ingredients:
FOR THE SPONGE
- 10 large eggs, separated
- ¼ tsp salt
- 180g caster sugar, divided into 2x 90g
- 3 x 8g packets of vanilla sugar (you can buy this online, or just substitute with normal sugar instead)
- 175g plain flour
- 1 tsp bicarbonate of soda
- 65g unsalted butter, melted
FOR THE GERMAN CHOCOLATE CUSTARD BUTTERCREAM
- 600ml whole milk
- 3 large egg yolks
- 60g cornflour
- 40g cocoa powder
- 150g dark chocolate, chopped (I used Dr. Oetker’s with 59% cocoa solids)
- 375g unsalted butter, softened
- 200g icing sugar, sifted
FOR THE CHOCOLATE CROWN DECORATIONS:
- 120g dark chocolate, chopped
- edible gold powder
FOR THE CHOCOLATE GANACHE:
- 200g dark chocolate, chopped (I used Dr. Oetker’s with 72% cocoa solids)
- 300ml double cream
- 25g unsalted butter, softened
YOU WILL ALSO NEED:
- 24cm round cake tin base (or a dinner plate of a similar diameter)
- Adjustable cake ring (or 23cm deep round spring-clip tin)
- Electric hand-held or free-standing mixer (I used my Kenwood)
- Silicone spatulas
- 3 large baking trays
- Wire cooling rack
- Small palette knife
- 2 piping bags
- 1 medium-sized star-shaped nozzle
- Baking paper
- Crown template (included above)
Method:
- Start by preparing the baking paper and sheets to bake the cake. Use the base of a 24cm baking tin to draw a circle on 8 pieces of baking paper. Then turn the baking paper so that the pencil marks are facing down and place onto the baking sheets.
- Preheat the oven to 190
- In a clean bowl, whisk the egg whites and salt until very foamy. Then gradually spoon in 90g of caster sugar and vanilla sugar, 1 tablespoon at a time, until you have a smooth, thick and glossy meringue. Set the meringue aside until needed.
- In a second (very large) bowl (you may want to weigh it beforehand so that you can divide the mixture better later), whisk together the 10 egg yolks and remaining 90g of caster sugar for 5-10 minutes until thick and mousse-like, and the mixture leaves a ribbon trail when you lift out the whisk (known as the ribbon stage).
- Gently fold the meringue into the egg yolk mixture until combined. Then sift in the flour and bicarbonate of soda and fold that in too, being careful not to knock out too much air. Finally, pour the melted butter down the sides of the bowl and fold that in too until all the ingredients are fully combined.
- Divide the cake mixture into eight equal portions (around 120g each) and spoon it into the circle on the 3 prepared baking trays. Carefully spread the mixture out thinly using a metal spoon or palette knife to fill the entire circle. Bake in the preheated oven for 5-8 minutes until puffy and lightly golden. Transfer to a wire cooling rack and then repeat this until all 8 sponges are baked. Then leave the sponges to cool completely.
- In the meantime, you can prepare the chocolate custard and melted chocolate for the buttercream. Pour 500ml of the milk into a pot and heat until just below boiling point. In a separate bowl, whisk together the egg yolks, cornflour, cocoa powder and remaining 100ml of milk together until smooth.
- Pour the hot milk over the egg mixture in a slow but continues stream while whisking constantly. Then pour the mixture back into the pot and set over a medium heat. Whisk for about 3-5 minutes until thickened, then transfer the custard to a shallow bowl. Cover the surface closely with clingfilm to stop a skin from forming and leave the custard to cool. You can put it in the fridge once it has started to cool slightly to speed up the process.
- Next, place the dark chocolate for the buttercream into a heatproof bowl and set over a pot of gently simmering water. Carefully melt the chocolate and then transfer it to another bowl where you can leave it to cool completely.
- While you are waiting for the sponges, custard and chocolate to cool, you can make the chocolate crown decorations. Using the same bowl as before, roughly chop 80g of the chocolate and melt it over the pan of simmering water, then remove from the heat. Finely chop the remaining 40g of chocolate, and stir it into the melted chocolate to cool it down (this is a shortcut method for tempered chocolate).
- Fill the melted chocolate into a small piping bag and snip off the bottom to create a small hole. Put the template (see a printable one I have made above) under a piece of baking paper set on a tray to pipe some chocolate crown decorations. Then leave to set before lightly brushing or spraying them with edible gold glitter powder or shimmer spray.
- Once the custard is cool, you can finish preparing the buttercream. In a large bowl, beat the softened butter for 2-3 minutes until really smooth and slightly paler in colour. Then add in the icing sugar, roughly half of it at a time and beat for 2-3 minutes until smooth. Next, spoon in the custard a little at a time whilst continuing to whisk, followed by the cooled melted chocolate. Beat the icing for a further minute or so until everything is well combined.
Set around ¼ of the chocolate custard buttercream aside for later.
- Using the base of a 23cm baking tin (or just a stencil made from the baking paper as I did (see above)), trim the cooled sponges so that they are all 23cm in diameter. Next, either place one of the sponges at the bottom of a 23cm deep cake tin, or onto a cake board set onto a plate/cake lifter and tighten a round adjustable cake ring around it.
- Spread about 1/7 of the remaining chocolate buttercream over the sponge in an even layer, then add the next sponge and repeat the process. Place the last sponge at the very top but don’t spread any buttercream over that. Transfer the cake to the fridge for 30 minutes to chill.
- Carefully remove the side of the tin or the cake ring from the cake. Spread some of the reserved buttercream around the sides of the cake to ensure the sides of the cake are smooth and all of the crumbs are caught (this is known as a crumb coat). Chill the cake in the fridge further 20 minutes.
- In the meantime, spoon the leftover buttercream into a piping bag fitted with a star-shaped nozzle.
- Also prepare the ganache by finely chopping the chocolate and placing it into a heatproof bowl. Pour the cream into a saucepan and warm over a medium heat until just below boiling point. Then pour it over the chocolate and cover the bowl with a dinner plate. Leave to stand for 2-3 minutes. Use a wooden spoon to stir the mixture until all the chocolate is melted and has formed a smooth ganache, then stir in the butter until melted.
- Remove the cake from the fridge. Place it onto a wire rack with some kitchen towel or baking paper below it to catch any drips. Pour over the ganache to cover the top and sides of the cake, then leave to set for 20-30 minutes.
- When the ganache starts to harden, use a knife to score the top of the ganache to mark out 12 equal pieces for slicing. Then pipe 12 buttercream rosettes around the top edge of the cake, one for each slice, and decorate with a chocolate crown.
