Ultimate Biscoff Birthday Cake With Italian Meringue Buttercream
Who doesn’t love the moment at a party when you all gather around and sing happy birthday (badly) while presenting a cake to someone with everyone smiling in the knowledge that a) it’s someone’s birthday and b) you’re about to get stuck into the cake in a matter of seconds? For me, it’s always a special moment, especially in an office environment when the recipient is mortified they’re getting so much attention. In my opinion, 3 pm office birthday cake tastes different to a standard cake but I have no idea why.
What makes that moment even better is if you’ve made that birthday cake! There is nothing I love more than making someone a birthday cake in their favourite flavour and surprising them with it on the day. It’s getting harder these days as I’m often asked to make cakes but as long as I get to see that big smile it’s more than worth it.
There are so many variations of sponge and icing, but after making this sponge a few times this is now my go-to recipe. The sponge is super light and fluffy as well as being moist and rich thanks to the generous amounts of sour cream. As this is a vanilla sponge I’d recommend using the best vanilla you can afford. This vanilla bean paste is my favourite and I save it for making a sponge where the vanilla is the star of the show. What also adds to the texture of this sponge is the use of egg whites. I like to sometimes use a carton of egg whites when I’m making a cake like this, but I don’t recommend using them for the icing, as they’re pasteurised and don’t whip up like a fresh egg white would.
This recipe yields nice flat players which are perfect for this kind of multi-layered cake. Here I have layered up 5 cakes alternating with Biscoff spread, Biscoff buttercream and also some crushed up biscuits which add another texture dimension to the cake. I have this set of cake pans, which are great for making multi-tiered cakes like the famous rainbow cakes that look so great in pictures. A few questions you might have before we begin…
What is Italian meringue buttercream?
Italian meringue buttercream takes a bit more effort and equipment, but if you have them then it’s more than worth the effort. It is made by whipping up egg whites and then cooking them by slowly pouring in a sugar syrup that’s been heated to the ‘hard ball’ stage which is 121 to 130 °C (250 to 266 °F). Once the meringue cools to room temperature you gradually whisk in butter and any flavourings and the result is a super light icing that’s less sweet than the traditional buttercream icing that you often have in homemade cakes.
In summary, Italian meringue buttercream is by far the best thing to ice a cake with. It takes more time but it’s incredibly delicious and not too sweet. Give it a try and I assure you that you won’t look back.
What is Biscoff?
Biscoff biscuits are caramelised biscuits that are thin, nice and crunchy and taste of caramel and cinnamon. You might have eaten them in the hairdressers as they’re often served alongside coffee. Biscoff is the brand name, and in Europe, the flavour is are more commonly known as speculoos and in the US it is often referred to as cookie butter. Originally they were simply biscuits, but in recent years they launched a spread that has taken much of the world by storm. You might have even seen it in the shops, but not realised what it is. Does this packaging look familiar? Here I’ve used the biscuits to decorate the cake, and the inside of the cake has layers of smooth Biscoff spread. I’ve also added Biscoff to the Italian meringue buttercream so it has that distinct flavour is laced throughout.
How to make the ultimate Biscoff birthday cake
Serves: 18 depending on how you slice it and how hungry you are
Time: 2hrs 30mins approx + cooling. I like to make the sponge a day or two before I need the cake so it’s less of a big job!
Skill: Medium
Equipment: A stand mixer, sugar thermometer and offset spatula are all pretty essential here. A cake board, icing scraper and turntable will also make your life a lot easier.
INGREDIENTS
For the vanilla cake:
400g self-raising flour
600g caster sugar
250g unsalted butter
1 tsp salt (6 grams)
7 egg whites (about 230g)
345g soured cream
2 tsp good quality vanilla bean paste or extract (I really love this one)
For the Italian Meringue Buttercream:
250g caster sugar
160ml water
7 egg whites (I don’t recommend using a carton of egg whites for meringue, so why not make pasta with those spare yolks?)
150g smooth Biscoff
450g unsalted butter, at room temperature
To decorate:
200g Smooth Biscoff spread, room temperature
I pack Biscoff biscuits (10 for the top, and the rest crushed to go in the layers and on the side of the cake)
50g Melted Biscoff spread (warmed for 30 seconds in the microwave)
METHOD
To make the sponges:
Preheat oven to 160°C/320°F and grease and line five 8" pans with parchment rounds. I use tins like these ones.
In a stand mixer using the paddle attachment, slowly combine the self-raising flour, caster sugar and a teaspoon of salt until it’s thoroughly mixed.
Add in the unsalted butter and on a low speed continue to mix until the mixture looks crumbly.
Slowly pour in the egg whites and mix on a slow speed until just incorporated then add a third of the soured cream at a time until just combined.
Add 2 tsp of vanilla bean paste or good-quality vanilla extract and mix being careful not to over mix as this will start to release the gluten in the flour! If you want to make a colourful cake now is the time to add in your gel food colouring or food colouring paste.
Divide the batter evenly between your prepared pans so you get even layers. I like to use an ice cream scoop to portion it out doing a dollop in each pan in turn. You could, if you are a perfectionist, weigh the batter and then divide it by 5 to get it exact.
Bake the sponges for 22 minutes or until a toothpick comes out with a few moist crumbs. If your oven has hot spots i’d suggest turning the tins if you can see one side colouring too much. Every oven varies so keep an eye on your cakes for about 20 minutes and take them out if they look done. Max should be 25 minutes as they aren’t very thick. Allow the cake to cool in the tin for 10 minutes and then turn out onto a wire rack to cool completely. If you’re assembling straight away, you could put the sponges in the freezer to cool quickly
To make the icing:
To make the Italian buttercream, put the water and sugar in a pan on medium heat along with a sugar thermometer to keep an eye on the temperature.
In a large bowl of a stand mixer with a whisk attachment add the egg whites ready to be whisked. It’s essential the bowl is grease-free as grease is NOT meringues friend and it can all end in tears, not tiers.
When the sugar syrup reads about 115°C/239°F, turn on the whisk and start whipping the egg whites at a high speed. When the syrup reaches the hardball temperature which is 121°C/250°F it’s go time and you’re going to ‘cook’ the meringue which is the base of the icing. With the mixer still running on high, slowly pour the sugar syrup down the side of the bowl in a slow steady stream taking care to avoid the beaters as you don’t want hot sugar on you.
Once all the sugar has been added, continue whipping the meringue on high until the bowl is room temperature which takes a little time so be patient. When it’s room temperature, turn the mixer to medium and start adding the butter in chunks of about a tablespoon at a time beating until it’s all fluffy and well combined. It might look like it’s curdling at this point but persevere and it will come back around as you add more butter. It’s important the meringue is room temp when you do this so the butter doesn’t melt.
Finally, add in the Biscoff and mix until it’s fully incorporated and a nice pale biscuit colour. This is now ready to be piped onto the cake.
To assemble:
You can use your creative flair here and layer it however you want, but I like to do it like this so you’re getting some variety. I don’t think your cake needs to look perfect, if we wanted perfect we’d buy them from a shop!
To assemble the cake, add about a tablespoon of Biscoff to the centre of the cake-board and smooth out - this is going to act as our ‘glue’ to keep the cake in place.
On top of this ‘glue’ add your first cake layer and gently press down so it ‘sticks’ then spread on about a third of Biscoff in a thin layer, and add half of the crushed biscuits.
Top with a layer of sponge, another thin layer of Biscoff spread and spread on a generous dollop of the Italian meringue buttercream then use a spatula to smooth it into an even later about a cm thick.
Add another cake layer and repeat as above.
Finally, for the last layer add a layer of the buttercream and the remaining crushed biscuits. Top this with the final sponge layer using the bottom of the sponge (which will be flatter) as the top.
Now it’s time to crown the cake with its final layer. Now I’m not a pro at this, so if it’s your first time I’d suggest watching a tutorial first. Someone like Chelsweets has amazing videos like this one that shows you step by step how to do it. For the crumb coat spread an even thin layer all over the cake using an offset spatula then refrigerate. This crumb coat does just what it says on the tin; it traps all the stray crumbs so you can get a smoother exterior. Chill in the fridge for about half an hour to allow it to set or in the freezer for 15 mins.
Add another layer of icing and use a spatula or icing scraper to get the sides as smooth as you can. I don’t worry too much about this but if you’re a perfectionist it can take some time! If you do it too well, people won’t believe you that it’s homemade!
I pipe 8-10 rosettes on the top depending on the size of nozzle you have and then crown each rosette with a biscuit. Make sure they’re touching so it creates a well for the final drizzle of spread.
Use the remainder of the crushed biscuits to decorate the bottom half of the cake. This is an excellent way to hide imperfections.
Finally, pour the gently warmed (not hot) Biscoff onto the top of the cake in the well made by the rosettes.
NOTES
This cake will keep well in an air-tight container for 3-4 days.
These sponges freeze really well so it’s a great idea to make the sponges ahead so you have less to do when you assemble.
You can also make the icing ahead and keep it in the fridge for a few days. Just make sure it comes back up to room temperature before you use it, and give it a really good stir before piping.
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