Anna Louise Some cakes are fashionable. They come and go with the seasons, driven by whatever happens to be trending. And then there are the classics — the ones that never go anywhere, because they were perfect to begin with.
Mary Berry’s coffee and walnut cake is one of those. I have been making this recipe for as long as I can remember, and I am utterly convinced it never goes out of style.
The sponge is light and properly coffee-flavoured — not a vague whisper of it, but an actual, satisfying depth of coffee that you can taste in every bite. The buttercream is smooth and rich. The walnuts give you a little bitterness and crunch that pulls the whole thing into balance. It is completely, quietly wonderful.
I am Anna Louise, and this is my tried-and-tested version of Mary Berry’s coffee and walnut cake — the one I have made for birthdays, for bake sales, for Sunday teas, and for absolutely no occasion at all except that it was a grey afternoon and I fancied baking. Here is everything you need to know to make it perfectly.
What Makes a Great Coffee and Walnut Cake?
Before I give you the recipe, I want to share a few things I have learned over the years, because they genuinely make a difference.
The coffee strength matters enormously. The most common reason a coffee and walnut cake disappoints is that the coffee flavour is too weak. You need a concentrated hit of coffee, not a diluted suggestion of it.
I use instant espresso powder dissolved in a small amount of boiling water — it gives a clean, intense coffee flavour without adding too much liquid to the batter. If you use regular instant coffee, make sure it is the strongest you can find and use slightly less water.
The all-in-one method works brilliantly here. Mary Berry uses her classic all-in-one sponge technique — everything into one bowl, beat together, done. It is fast, reliable, and produces a beautifully light, even crumb every time. The key is that your butter must be properly, genuinely soft before you start.
Beating the butter first for the buttercream makes all the difference. I say this repeatedly to anyone who asks about buttercream and I will say it here too. Beat the butter alone for three to four minutes before you add anything else.
It should turn pale and almost white. This step creates a light, airy buttercream that is genuinely lovely to eat, rather than a heavy, overly sweet paste.
Ingredients for Mary Berry Coffee and Walnut Cake
For the Coffee Sponge
- 225g unsalted butter, softened to room temperature
- 225g caster sugar
- 4 large eggs
- 225g self-raising flour, sifted
- 2 tsp baking powder
- 2 tbsp instant espresso powder dissolved in 2 tbsp boiling water, cooled completely
- 100g walnut pieces, roughly chopped
For the Coffee Buttercream
- 175g unsalted butter, softened
- 350g icing sugar, sifted
- 1½ tbsp instant espresso powder dissolved in 1½ tbsp boiling water, cooled completely
- 1–2 tbsp whole milk, to loosen if needed
To Decorate
- 8–10 walnut halves
- Optional: a light dusting of icing sugar
How to Make Mary Berry Coffee and Walnut Cake — Step by Step
Step 1 — Make Your Coffee Liquid First
Dissolve the espresso powder in the boiling water, stir well, and set aside to cool completely. I always do this before I do anything else — it needs to be at room temperature before it goes into the batter or it will start to cook the eggs. This takes about ten minutes, so get it out of the way first.
Step 2 — Preheat and Prepare
Preheat your oven to 180°C / 160°C fan / Gas 4. Grease and line two 20cm round sandwich tins with baking parchment.
Step 3 — Make the Coffee Sponge Batter
Put the softened butter, caster sugar, eggs, sifted flour, and baking powder into a large mixing bowl. Add the cooled coffee liquid. Beat everything together with an electric hand whisk for two to three minutes until the batter is smooth, pale, and slightly increased in volume. Scrape down the sides of the bowl halfway through and give it one final mix to make sure everything is evenly incorporated.
Step 4 — Add the Walnuts
Fold the roughly chopped walnuts through the batter with a spatula. Keep them fairly chunky — you want actual pieces of walnut in each slice, not just a powdery flavour.
Step 5 — Fill the Tins and Bake
Divide the batter evenly between the two prepared tins. I weigh each tin as I fill it to make sure the layers are equal — it makes assembling the finished cake so much easier. Smooth the tops and bake on the middle shelf for 25 to 30 minutes, until golden, well risen, and a skewer inserted into the centre comes out clean.
Step 6 — Cool Completely
Leave the sponges in their tins for five to ten minutes, then turn out carefully onto a wire rack. They must be completely cool before you make or apply the buttercream — at least 40 minutes, or longer if your kitchen is warm.
Step 7 — Make the Coffee Buttercream
Beat the softened butter alone in a large bowl for three to four minutes until it is very pale, light, and fluffy. This is the step most people rush and it really is worth the time — properly beaten butter gives you a completely different buttercream.
Add the sifted icing sugar in two batches, beating well after each addition. Pour in the cooled coffee liquid and beat until smooth. If the buttercream feels too stiff, add a splash of whole milk and beat again until it reaches a spreadable consistency.
Step 8 — Assemble and Decorate
Place one sponge on your serving plate or cake stand. Spread a generous layer of coffee buttercream over the surface — do not be shy with it. Carefully place the second sponge on top, pressing down very gently to level it.
Spread the remaining buttercream over the top. I love using a palette knife and creating a simple swirl — it looks elegant without requiring any particular skill. Press the walnut halves around the top edge to decorate.
My Top Tips for Mary Berry Coffee and Walnut Cake
Your butter must be properly soft. I mean genuinely soft — if you press your finger into it, it should leave an indent without any resistance. Cold butter will not incorporate properly in an all-in-one batter and you will end up with a lumpy, uneven sponge.
Take it out of the fridge at least an hour before you bake, or cut it into cubes and leave it near your oven for 20 minutes.
Never add warm coffee liquid to your batter. I mentioned this in the method and I am repeating it here because I have seen it go wrong. Warm liquid starts to cook the eggs and can cause the batter to curdle. Make the coffee liquid first, set it aside, and let it cool fully before it touches anything else.
Toast the walnuts. Buy whole walnut halves rather than pre-chopped pieces — pre-chopped walnuts often taste stale. Toast them in a dry frying pan for a few minutes until they smell fragrant and nutty, then chop roughly. The difference in flavour is significant.
Weigh your batter between the tins. Even layers make for a much better-looking finished cake. It takes about 30 seconds and is absolutely worth doing.
Beat the butter for the buttercream until it looks nearly white. I know it feels like a long time, but this is what separates a truly lovely coffee buttercream from a mediocre one. Pale, fluffy butter means a light, airy buttercream. Do not skip this step.
Chill the assembled cake for 20 minutes before serving if you are taking it somewhere. It firms up slightly and slices so much more cleanly. Always bring back to room temperature before eating.
Serving Suggestions
Coffee and walnut cake is one of those bakes that needs very little dressing up. A proper pot of tea — I am partial to a good Assam — is all it really needs alongside it. For a dinner party, a small slice with a little scoop of vanilla ice cream or a spoonful of lightly whipped cream is quietly spectacular.
How to Store Mary Berry Coffee and Walnut Cake
At room temperature: Fine for up to one day in a cool kitchen. The buttercream can become very soft in warm conditions.
In the fridge: Store in an airtight container for up to 3 days. Bring to room temperature for 20 to 30 minutes before serving — cold buttercream straight from the fridge is not nearly as good.
In the freezer: Freeze the unfrosted sponge layers for up to 3 months, wrapped tightly in cling film and foil. Make the buttercream fresh when you are ready to assemble.
Mary Berry Coffee and Walnut Cake
Ingredients
Method
- Dissolve espresso powder in boiling water. Set aside to cool completely.
- Preheat oven to 180°C / 160°C fan / Gas 4. Grease and line two 20cm sandwich tins.
- Add butter, caster sugar, eggs, flour, baking powder, and cooled coffee liquid to a large bowl. Beat with an electric whisk for 2–3 minutes until smooth and pale.
- Fold in chopped walnut pieces.
- Divide equally between tins. Bake 25–30 minutes until golden and a skewer comes out clean.
- Cool in tins 10 minutes, then turn out onto a wire rack. Cool completely.
- Beat softened butter alone for 3–4 minutes until very pale. Add icing sugar in two batches. Add cooled coffee liquid. Beat until smooth. Add a splash of milk if needed.
- Sandwich sponges with half the buttercream. Spread remainder on top. Decorate with walnut halves.
Notes
Always cool the coffee liquid before adding to the batter. Beat butter alone for 3–4 minutes before making buttercream — do not rush this. Toast walnuts in a dry pan for better flavour. Bring refrigerated cake to room temperature 20–30 minutes before serving. Unfrosted sponge layers freeze well for up to 3 months.
Frequently Asked Questions About Mary Berry Coffee and Walnut Cake
Can I use brewed coffee instead of instant espresso powder?
You can, but it needs to be very strong — a double espresso brewed and cooled works well. Avoid using regular filter coffee as it is too weak and will add too much liquid. Instant espresso powder gives the most consistent, reliable result and is what I always use.
Why did my coffee sponge sink in the middle?
This is almost always caused by one of three things: opening the oven door too early (wait at least 20 minutes), an oven that was not properly preheated, or slightly underbaked sponge. Always do the skewer test and make sure it comes out completely clean before you take the tins out.
Can I make this coffee and walnut cake without nuts?
Yes, simply leave the walnuts out entirely. The coffee sponge and buttercream are lovely on their own and the cake is perfectly balanced without the walnuts. You could replace them with chocolate chips if you’d like something in the batter.
How do I get clean slices when cutting?
Use a sharp knife dipped in hot water and wiped dry between each cut. This cuts through the buttercream cleanly and gives you neat, professional-looking slices.
Can I make this cake ahead of time?
Yes. The unfrosted sponge layers keep well at room temperature, wrapped in cling film, for up to two days. Freeze for up to three months. Assemble and frost on the day you plan to serve for the best appearance and texture.
Can I turn this recipe into coffee and walnut cupcakes?
Absolutely. This batter makes approximately 18 cupcakes. Fill cupcake cases two-thirds full and bake for 18 to 20 minutes at the same temperature. Top each with a swirl of coffee buttercream and a walnut half.
