Mary Berry Walnut and Coffee Sandwich Cake

I’ve made this cake more times than I’ve overboiled the kettle, and that’s saying something. It was my gran’s favourite—she always insisted it was the only proper cake to have with a cup of coffee. The first time I tried to make it, I used instant coffee granules straight from the jar… without dissolving them. Crunchy frosting, anyone?

This nearly flopped on me when I rushed the icing and ended up with a greasy mess (spoiler: softened butter doesn’t mean melted). But once I nailed the strong coffee, walnut texture, and that silky-smooth buttercream? Game changer. Let me show you how I fixed it—and how to avoid the crunchy-coffee disaster.

What Makes This Recipe Special

This one hits that perfect nostalgic note: sweet, nutty, and bold from the coffee, without being cloying. Most coffee walnut cakes are either too dry or taste like instant granules. Mary Berry’s version gets it just right—with a few tweaks.

Here’s why it works:

• All-in-one method means it’s quick—but I found beating the eggs in last gives even better rise.
• Very strong coffee (I use espresso from my stovetop moka pot) brings proper flavour. Weak coffee just gets lost.
• And the buttercream? Heavenly. But don’t rush it—if the butter’s too cold, it curdles.

INGREDIENTS + WHY THEY MATTER

• Self-raising flour – Gives the sponge its lift. I once ran out and added baking powder to plain flour—worked, but not quite as airy.
• Baking powder – Just a little extra lift to support the walnuts.
• Walnuts (100g) – Finely chopped so they don’t sink. Adds crunch and depth. Toasting them first? Even better.
• Baking spread – Straight from the fridge! This shocked me, but it actually emulsifies beautifully.
• Caster sugar – Light and quick to dissolve.
• Eggs – Bind and lift. Room temp eggs mix better.
• Very strong coffee – The star. Needs to be brewed, not instant granules. Trust me.

Icing:

• Butter – Softened, not melted. I leave mine out for 30 mins.
• Icing sugar – Sifted, or you’ll get lumps.
• Strong coffee again – No shortcuts here. It makes the icing sing.

Ingredient Swaps That Hold Up

• No walnuts? Pecans work—milder, slightly buttery.
• Gluten-free? I tested with Doves Farm self-raising GF flour—worked beautifully. Just be gentle with mixing.
• Dairy-free? I’ve had luck with Flora Plant Butter and a splash of almond milk in the icing to loosen it.

Mistakes I’ve Made (And How to Avoid Them)

What Went Wrong	Why It Happens	How to Fix It
Coffee taste was too weak	Used regular brewed coffee	Brew a double espresso or use instant paste
Cake sank in middle	Batter was overmixed or tins too full	Mix just until combined + level tins
Icing split	Butter was too cold	Let it soften fully—room temp is key
Walnuts sunk to bottom	Too coarsely chopped	Chop finely, toss with a spoon of flour

How to Make Mary Berry’s Walnut and Coffee Sandwich Cake

1. Prep the tins – Grease and line two 20cm sandwich tins. I use my old metal ones—they give better rise than silicone.
2. Make the batter – In a large bowl, mix flour, sugar, baking powder, and chopped walnuts. Add baking spread, eggs, and coffee. Beat until light and fluffy—don’t overdo it.
3. Bake – Divide evenly and bake at 180°C (160°C fan) for 25–30 mins. When golden and springy, they’re done. Cool in tins 10 mins, then on racks.
4. Make the icing – Beat soft butter with half the icing sugar and coffee. Add the rest, beat until smooth. If stiff, add ½ tsp coffee at a time.
5. Assemble – Place one cake upside down. Spread half the icing. Add top layer. Spread rest on top and swirl with a spoon for that classic vintage look.

Tips From My Kitchen

• I toast the walnuts first for extra depth—just 5 mins in a dry pan.
• I use a stovetop espresso maker for the coffee—it’s intense and perfect.
• My fan oven runs hot, so I check at 23 mins.
• I warm my mixing bowl with hot water and dry it—helps everything blend faster.

Storage + Serving

• Keeps for 4–5 days in a tin, or longer in the fridge (but let it come to room temp before eating).
• Freezes well—wrap whole or sliced, and thaw overnight.
• Serve with a proper cup of strong coffee or milky tea. Lovely with whipped cream or a cheeky drizzle of coffee liqueur if you’re feeling fancy.

FAQs

Q: Can I use instant coffee instead of brewed?
A: Only if it’s coffee paste or made super strong. Instant granules on their own don’t give enough depth.

Q: Why did my cake come out dry?
A: Could be overbaked—check your oven temp with an oven thermometer. And don’t skip the coffee—it adds moisture too.

Q: Can I make this as a traybake?
A: Yes! Use a 9×13 tin and bake for about 25 mins. Great for slicing into squares and freezing.

Q: Can I decorate it more?
A: Absolutely. Add walnut halves on top or pipe the icing for a fancy finish.

Q: Can I make the icing less sweet?
A: Try swapping 25g of icing sugar for cream cheese—it softens the sweetness and gives a tang.

Try More Recipes:

• Mary Berry Battenberg Cake Recipe
• Mary Berry Lemon Yoghurt Cake
• Mary Berry Coffee and Walnut Sponge Cake
• Mary Berry Apple And Apricot Cake