This chocolate stout cake is a deep, rich, single-layer traybake that serves nine to twelve — a glossy, intensely chocolatey sponge made with stout, a double shot of espresso, cocoa powder, sour cream and salted butter, topped with a thick, silky cream cheese frosting spiked with tahini, vanilla and flaky sea salt, finished with toasted sesame seeds. The sponge is inspired by Nigella Lawson's celebrated chocolate Guinness cake, with one addition: a double shot of espresso, which is not there to add coffee flavour but to deepen and amplify the cocoa. The frosting is nutty from the tahini, sweet and fragrant from the vanilla, and brought into perfect balance by the salt. The combination of deep, bitter, earthy sponge and creamy, subtly nutty frosting is one of my new favourite pairings, and this cake is one I will be making again and again.

About The Signature Series

The Signature Series is a new series on One Pot One Portion running throughout the current series of The Great British Bake Off. Each week I will be sharing the bake I would make for that week's signature challenge — if I were in the tent, which sadly I am not. This chocolate stout cake is the first recipe in the series, inspired by stout cake week.

Why I Created This Recipe

A new series of The Great British Bake Off has started, and every week I am going to be sharing what I would make for the signature bake if I were on the show. Which, sadly, I am not.

This week the signature challenge was a stout cake, and I knew immediately where I wanted to start. Nigella Lawson's chocolate Guinness cake is, in my view, one of the best chocolate cake recipes ever written. The principle is straightforward: stout and butter are melted together with cocoa and sugar to create a glossy, deeply flavoured base that gives the finished cake a richness and depth that a conventional creamed sponge simply cannot replicate. I have kept that foundation almost entirely intact, adding only a double shot of espresso — not for coffee flavour, but because espresso is one of the most effective tools in a baker's arsenal for enhancing the flavour of cocoa. It makes the chocolate taste more like itself.

The frosting is where I have made this recipe my own. A classic cream cheese frosting felt right as a starting point — the tanginess of the cream cheese is a perfect counterpoint to the deep sponge — but I wanted to take it somewhere more interesting. Tahini was the answer. Its deep, nutty, faintly bitter flavour echoes the cocoa and the stout without competing with either, and alongside the vanilla and the flaky sea salt it creates something that tastes genuinely unexpected and genuinely extraordinary. I adore this bake — and I will be returning to it far beyond the end of this GBBO series.

The Inspiration

Nigella Lawson's chocolate Guinness cake — published in her cookbook Feast — is one of the most widely made and most loved chocolate cakes in British home baking, and for very good reason. The method of melting the butter and stout together before adding the dry ingredients produces a batter that is almost liquid before baking and sets into something extraordinarily moist and deeply flavoured — a result you simply cannot achieve by creaming butter and sugar in the conventional way.

This recipe takes that method as its foundation and keeps it largely intact, because it is very nearly perfect as it is. The only addition is a double shot of espresso added with the stout — 60ml of freshly brewed espresso that amplifies the cocoa without adding a perceptible coffee flavour to the finished cake. The frosting is entirely different from Nigella's original, which uses cream cheese and icing sugar without tahini — this version takes the cream cheese base and adds tahini, extra vanilla and flaky sea salt to create something that feels entirely new alongside the familiar, beloved sponge.

Credit where it is firmly due — the bones of this cake belong to Nigella.

Why Espresso in a Chocolate Cake?

The double shot of espresso in this cake is one of the most useful baking techniques worth understanding — because it is not about adding coffee flavour. It is about making the chocolate taste better.

Cocoa powder and coffee share many of the same aromatic compounds — the same roasted, slightly bitter, deeply complex flavour molecules that make both ingredients so compelling. When a small amount of coffee is added to a chocolate batter, it does not produce a coffee-flavoured cake. Instead it enhances and amplifies the existing cocoa flavour, making the chocolate taste more intense, more rounded and more fully itself. The espresso essentially turns up the volume on the cocoa without adding a new flavour of its own.

The Tahini Frosting — Why It Works

Tahini is a paste made from ground sesame seeds — used widely across Middle Eastern, North African and Mediterranean cooking, and increasingly present in Western baking and desserts for its distinctive deep, nutty, slightly bitter flavour.

In a sweet context, tahini behaves somewhat like peanut butter or almond butter — adding richness, nuttiness and a slight earthiness to whatever it is stirred into. But its flavour is more delicate and more complex than either, with a faintly spiced, almost smoky quality that makes it a particularly interesting ingredient in baking.

In this frosting, the tahini is paired with cream cheese, icing sugar (powdered sugar), double cream (heavy cream), vanilla and flaky sea salt. The cream cheese provides the tangy, creamy base; the icing sugar sweetens; the double cream gives body and a smooth, slightly looser consistency; the tahini adds depth and nuttiness; the vanilla adds fragrance and warmth; and the salt is what ties everything together, preventing the frosting from tasting sweet and one-dimensional and keeping every element in balance.

The cornflour (cornstarch) — borrowed from Nigella's original frosting method — is not purely structural. It stabilises the cream cheese and thickens the frosting slightly, giving it the body and spreadability to sit cleanly on top of the cake without sliding or weeping. Do not leave it out.

The toasted sesame seeds scattered over the top are both decorative and deliberate — they echo the tahini in the frosting and add a gentle, nutty crunch that is the perfect final texture against the soft sponge and smooth cream.

Why You'll Want to Make This Recipe

One of the Great Chocolate Cakes

Nigella Lawson's chocolate stout cake method produces a sponge that is extraordinarily moist, deeply chocolatey and rich in a way that conventional chocolate cakes rarely achieve. Adding the espresso takes it even further. This is a cake worth making for any occasion — or no occasion at all.

The Tahini Frosting

The combination of cream cheese, tahini, vanilla and flaky sea salt is one of the most interesting frostings on this blog — nutty, creamy, faintly bitter and perfectly balanced. It transforms a great chocolate cake into something genuinely memorable.

Serves Nine to Twelve

Baked in a 9 inch square tin, this cake serves nine to twelve generously — ideal for a gathering, a celebration or a week of very good afternoon slices. It keeps well and the flavour deepens over the first day or two.

Part of The Signature Series

This is the first recipe in The Signature Series — a collection of bakes inspired by the current series of The Great British Bake Off. Each one is a considered, carefully developed recipe that takes the week's theme and makes it entirely its own.

My Top Tips for the Perfect Chocolate Stout Cake

• Use a good quality stout — Guinness is the classic choice and gives a reliable, well-rounded result. Other stouts work well too; a chocolate stout will give a deeper, more intensely chocolatey result if you want to amplify the cocoa flavour even further.
• Use a freshly brewed double shot of espresso — around 60ml. A strong instant coffee dissolved in 60ml of hot water is a workable substitute but a proper espresso gives a more rounded, less harsh result. The espresso should be hot when it goes into the pan with the stout and butter.
• Melt the butter into the stout and espresso over a medium heat — do not rush it or boil it. You want the butter to melt gently and the mixture to come together smoothly before the cocoa and sugar go in.
• Whisk the cocoa and sugar into the warm stout mixture thoroughly until completely dissolved and smooth. Any lumps of cocoa at this stage will remain in the finished cake.
• Let the stout and butter mixture cool for a couple of minutes before adding the sour cream and eggs. Too hot and the eggs will begin to cook before they are incorporated — the mixture should feel warm rather than hot to the touch.
• Whisk the sour cream, eggs and vanilla in vigorously — this is the stage at which the batter comes together and develops its glossy, smooth consistency. Do not be tentative; a confident whisk gives a better result.
• Once the flour and bicarbonate of soda (baking soda) go in, whisk until just smooth — do not over-work. The batter will be very liquid, which is correct and is exactly what gives the finished cake its extraordinary moisture.
• Bake for around 45 minutes — check from 40 minutes with a skewer or thin knife. It should come out clean with no wet batter attached. The cake is very moist and a few damp crumbs on the skewer are fine; what you are looking for is no liquid batter.
• Leave the cake to cool completely in the tin before adding the frosting. The frosting contains cream cheese and cream and will melt and slide off a warm cake — patience here is essential.
• For the frosting, whisk the cream cheese until smooth before adding anything else. Starting with lumpy cream cheese will result in a lumpy frosting regardless of how much you whisk afterwards — get it completely smooth first.
• Sift the icing sugar (powdered sugar) and cornflour (cornstarch) together into the cream cheese. Sifting prevents lumps and ensures the cornflour is evenly distributed through the frosting.
• Add the double cream, tahini, vanilla and salt last and whisk until the frosting is thick, smooth and spreadable. Do not over-whisk once the cream goes in — the frosting can go from perfectly thick to over-whipped very quickly. Stop as soon as it holds its shape.
• Toast the sesame seeds in a dry pan over a medium heat for two to three minutes until golden and fragrant before scattering over the top — untoasted sesame seeds are pale and flavourless in comparison. Watch them carefully as they can burn quickly.

Storage

Storing

Once frosted, store the cake covered in the fridge for up to four days. The sponge improves over the first day or two as the flavours develop and the crumb settles — this is one of those cakes that is genuinely better on day two. Remove from the fridge 20–30 minutes before serving to allow the frosting to come to room temperature and soften slightly.

Freezing

The unfrosted sponge freezes well — wrap tightly in cling film (plastic wrap) and freeze for up to three months. Defrost overnight in the fridge or at room temperature, then frost as per the recipe once fully defrosted. The frosted cake is not ideal for freezing as cream cheese frostings can weep and become grainy on defrosting.

Dietary Variations

Gluten-Free

Replace the plain flour (all-purpose flour) with a gluten-free plain flour blend and ensure the bicarbonate of soda (baking soda) is gluten-free. Check the stout label too — most stouts contain barley and are not gluten-free, so look for a certified gluten-free stout or substitute with a gluten-free dark beer. All other ingredients are naturally gluten-free.

Without Tahini

If you do not have tahini or prefer a more classic frosting, simply leave it out — the cream cheese, icing sugar, vanilla and salt alone make a beautifully simple and very good frosting. The nutty depth that the tahini adds will be absent but the balance of tangy cream cheese and flaky salt against the rich sponge is still an excellent combination. Alternatively, a tablespoon of smooth peanut butter or almond butter in place of the tahini gives a similarly nutty result with a slightly different flavour.

Frequently Asked Questions

What stout should I use?

Guinness is the classic choice and the one most widely associated with this style of cake — it gives a reliable, well-rounded result with a slightly bitter, malty quality that works beautifully with the cocoa. Other stouts work equally well; a chocolate stout will give a deeper, more intensely chocolatey result. Avoid very sweet or flavoured stouts, which can make the cake cloying.

Why does the recipe use espresso if it is not supposed to taste of coffee?

Because espresso and cocoa share many of the same aromatic compounds, adding espresso to a chocolate batter enhances and amplifies the existing cocoa flavour without adding a perceptible coffee taste to the finished cake. It makes the chocolate taste more intense and more rounded — more like itself. See the full explanation in the section above.

Why is there cornflour in the frosting?

The cornflour (cornstarch) stabilises the cream cheese frosting and thickens it slightly, giving it the body and spreadability to sit cleanly on top of the cake without sliding or weeping. It is a technique from Nigella Lawson's original recipe and a very effective one — do not leave it out.

Can I make this as a round cake rather than a square traybake?

Yes — use a 9 inch round cake tin and follow exactly the same method and timing. The depth of the batter will be slightly different depending on the tin dimensions, so check from 40 minutes with a skewer rather than relying on the timer. A round cake presents beautifully with the white frosting and sesame seeds — perhaps even more dramatically than the square.

Can I make the cake in advance?

Yes — the unfrosted sponge keeps well wrapped at room temperature for up to two days, or in the fridge for up to four days. It can also be frozen for up to three months. Frost on the day you plan to serve it, or up to a day in advance — the frosted cake keeps well in the fridge for up to four days.

What is The Signature Series?

The Signature Series is a series on One Pot One Portion running throughout the current series of The Great British Bake Off. Each week I share the bake I would make for that week's signature challenge — a considered, carefully developed recipe that takes the week's theme and makes it entirely its own. This chocolate stout cake is the first recipe in the series.