This coffee and walnut cake recipe gives you a soft, well-structured layer cake where the coffee flavour is present throughout, not just in the icing. The walnuts go into the batter itself, so every slice has a little texture rather than just a decorated top. The filling and topping use the same coffee buttercream mixture, which keeps things simple and gives the cake a consistent flavour all the way through.
Only basic kitchen equipment is needed. Everything comes together with a hand mixer and two standard 20 cm cake tins.
About the Recipe
The batter follows a straightforward creaming method. Butter and sugar are beaten until pale, eggs are added gradually, and then the dry ingredients go in along with dissolved instant coffee. Splitting the batter between two tins and sandwiching them with buttercream gives you a proper layer cake without complicated assembly.
The coffee buttercream uses melted butter, which makes it easy to beat smooth. It needs time in the fridge or at room temperature to firm up before spreading, so factor that into your timing.
Why You Will Love This Recipe
The coffee flavour here comes through clearly in both the sponge and the buttercream. Using instant coffee granules dissolved in hot water means you can control the strength, and the quantities in this recipe produce a cake where the coffee is noticeable without being bitter.
The walnuts in the batter add a mild crunch that works well against the soft sponge. The whole cake, including baking and cooling, can be done in a couple of hours, and it stays good for three days in an airtight container.
Cooking Tips
The most common issue is spreading the buttercream before it has firmed up enough. If it is still too soft, it will slide off the cake rather than hold its shape. Give it at least 20 to 30 minutes in the fridge before you try to spread it.
Make sure the sponge layers are fully cool before assembling. A warm sponge will soften the buttercream immediately. When dividing the batter between the two tins, weighing each tin helps you get even layers so the cake sits level once stacked.
Top Tips
- Dissolve the coffee granules completely in hot water before adding to the batter. Undissolved granules can leave bitter spots in the sponge.
- Beat the butter and sugar for a full 3 to 4 minutes until the mixture looks noticeably pale and fluffy. This affects how well the cake rises.
- Add the beaten eggs gradually, a little at a time. Adding them all at once can cause the batter to curdle.
- Let the buttercream firm up in the fridge before spreading. If it is too loose, it will not hold between the layers.
- Line the cake tins with greaseproof paper and grease the sides well. This makes it much easier to remove the sponges cleanly after baking.
- Cool the sponge layers completely on a wire rack before assembling. Even slight warmth will soften the buttercream too much to spread neatly.
Serving and Storing Suggestions
Slice the cake once the buttercream has fully set. It serves well at room temperature. If the kitchen is warm, keep it in the fridge and bring it out about 20 minutes before serving so the buttercream softens slightly.
Store in an airtight container. The cake stays good for up to three days. Avoid freezing once assembled, as the buttercream texture changes on thawing. You can bake and freeze the plain sponge layers separately and make the buttercream fresh when needed.
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Nutrient Benefits
Walnuts provide protein, fibre, healthy fats, magnesium and copper. Eggs contribute protein and B vitamins to the sponge. This is a treat cake with a good amount of butter and sugar, but the walnuts do add some nutritional value per slice compared to a plain sponge. If you are curious about coffee, our article on what your morning filter coffee does for you covers some of its ordinary nutritional properties.
Coffee Walnut Cake
Ingredients
- 350 gms Caster Sugar
- 350 gms, unsalted, softened Butter
- 6 , beaten Eggs
- 150 gms, chopped Walnuts
- 350 gms Maida
- 1 tsp Baking Powder
- 2 tblsp, dissolved in 2 tblsp hot water Instant Coffee Granules
- For the filling and topping:
- 600 gms Icing Sugar
- 250 gms Unsalted Butter
- 6 tblsp, dissolved in 4 tblsp boiling water Instant Coffee Granules
- 8 tblsp Cream
- 50 gms, chopped Walnuts
Instructions
- Beat the butter and sugar in a bowl until light and creamy.
- Add the eggs, beating all the time.
- Add the walnuts, maida and baking powder.
- Add the dissolve coffee and mix well until combined.
- Divide the mixture between two 20 cm greased cake tins (lined with greaseproof paper) and spread evenly.
- Place the tins in a preheated oven at 180C/350F and bake for 25 minutes or until the cakes are golden brown on top.
- Gently remove the cakes from the tin and keep them on a wire rack to cool completely.
- Meanwhile, to make the filling and topping, heat butter in a small pan for a minute and keep aside.
- Add the icing sugar into a large bowl and pour the melted butter.
- Add the cream and dissolved coffee.
- Beat well until smooth.
- Now add the chopped walnuts and keep it in a fridge or outside till it is thick and almost set.
- Spread half of the mixture on one of the cakes and place the other on top (like a sandwich).
- Spread the remaining mixture on top.
- Garnish with walnuts.
- Store in an airtight container.
- This stays good for 3 days.
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Frequently Asked Questions
Can I use salted butter instead of unsalted butter?
It is better to use unsalted butter as the recipe specifies. Salted butter adds an unpredictable amount of salt to both the sponge and the buttercream, which can affect the overall flavour. If unsalted butter is not available, use salted butter but leave out any additional salt, and be aware the buttercream may taste slightly different.
What type of instant coffee works best in this recipe?
Any standard instant coffee granules work well. The recipe uses 2 tablespoons in the sponge and 6 tablespoons in the buttercream, so the coffee flavour is quite present. If you prefer a milder result, reduce the quantity in the buttercream slightly. Avoid using brewed filter coffee as a substitute because it adds extra liquid and will alter the batter consistency.
My buttercream is too runny to spread. What should I do?
This is the most common issue with this recipe. The buttercream uses melted butter, so it starts out quite liquid. Place it in the fridge for 20 to 30 minutes, checking every 10 minutes or so, until it thickens to a spreadable consistency. Do not leave it too long or it will set solid. If it has gone too firm, leave it at room temperature for a few minutes and stir before using.
Can I make this cake without eggs?
This recipe uses 6 eggs, which provide structure and lift to the sponge. Replacing them requires a different approach to the batter. If you need an egg-free version, it is better to use a recipe developed specifically without eggs. Our Basic Eggless Chocolate Cake gives a good example of how an eggless sponge is structured differently.
How do I know when the sponge is fully baked?
The recipe gives 25 minutes at 180 degrees C as a guide, but ovens vary. The sponge is ready when the top is golden brown and a skewer inserted into the centre comes out clean with no wet batter on it. The edges will also start to pull away slightly from the sides of the tin. If the top is browning too quickly before the centre is set, cover loosely with foil and continue baking.
