Walnut Cake with Coffee Frosting
This incredible walnut cake has layered soft, delicious yellow sponge cakes soaked with a flavorful rum syrup for an extra moist dessert. Roasted walnuts add a crunch and taste that works perfectly with rich coffee icing.
Sound tasty? Then you would love some of my other desserts with walnuts like this Chocolate Walnut Brownie recipe, Chocolate Kiev Cake, and these amazing Pistachio Walnut Baklava Rolls.
Walnut Cake Recipe
This walnut cake recipe is one that I’ve made often through the years. Admittedly, it isn’t exactly a cake that can be thrown together in 30 minutes. However, good things take time, and this incredible dessert is no exception.
There are several components to this walnut cake recipe, but each one is essential because it brings something crucial to the flavor profile. The entire dessert is a perfectly balanced treat that will make you the most popular person at whichever party you bring it to!
Just follow the instructions I lay out for you below, and I promise—you can absolutely make this walnut cake recipe!
Coffee Walnut Cake
Let’s talk about the flavor profile for a minute. It’s hard to think of a flavor combination I like more than coffee and walnuts. I know that may seem a bit random, but I promise you it’s way better than peanut butter and jelly or any other duo you can think of!
Don’t imagine that you can simply chew some walnuts and sip coffee and get the experience I’m talking about, however. What makes this coffee walnut cake so irresistible is that the walnuts are roasted, which brings out those rich notes and mellow flavor profile that pairs perfectly with acidic coffee.
Coffee Frosting
If you have never tried coffee frosting, you’re missing out big time! In fact, I’ll often make this buttercream to go on top of a simple cake if I’m in a rush. I’ve tried a lot of icings over the years, and this coffee frosting is still one of my favorites!
Although it’s very easy to make, buttercream frosting can be a bit temperamental. If you’re new to the world of buttercream icing, there are a few tips and tricks you need to know to make sure you nail the perfect coffee frosting.
Tips for Getting the Perfect Coffee Frosting
- Use instant coffee. Make sure to use instant coffee in this recipe, not normal coffee grinds.
- Sift your cocoa powder. Sifting will break up any clumps in the cocoa powder while aerating it, ensuring the most accurate measurements as you are making this walnut cake.
- Use Cool Whip for the whipping cream: it incorporates better into the cream and you’ll have a higher success rate rather than using actual heavy cream (which you’ll whip).
Rum Soaked Cake
Don’t worry—just because this is a rum-soaked cake doesn’t mean that kids can’t enjoy it. If you prefer this cake to be alcohol-free, just substitute the rum with rum flavoring which contains no alcohol.
As a side note – with only a couple tablespoons of rum in the whole cake, there’s no worry about getting drunk on a slice of cake.
The reason there is rum in this recipe is that it adds a rich, buttery flavor to the cake layers. It also adds even more moisture to this cake, without making it soggy.
The easiest way I’ve found to add rum to the walnut cake is to mix it with water and sugar (as noted below in the recipe card), then add it into a squeeze bottle. Drizzle it over each of the yellow cake mixtures, and you’ve got an incredible rum-soaked cake!
More Cake Recipes:
Walnut Cake with Coffee Frosting
This walnut cake has moist layers of rum-soaked yellow cake nestled between rich coffee frosting. Roasted walnuts add crunch, flavor and presentation to this incredible dessert.
Ingredients
Yellow Sponge Cake
- 8 eggs
- 2 cups sugar
- 2 cups all-purpose flour
- 2 tsp baking powder
- 6 Tbsp melted butter
- 4 Tbsp hot water
- 2 Tbsp vanilla extract
Rum Syrup
- 1/2 cup granulated sugar
- 3 tbsp Bacardi Rum (or any other good Rum you prefer)
- 1 1/2 cups water
Coffee Cream
- 8 oz Cool Whip
- 2 tbsp Instant Coffee or 2 Via Starbucks packet
- 1/4 cup cocoa powder, sifted
- 12 oz unsalted butter room temperature (12 oz= 1 1/2 cups)
- 1 1/2 can dulce de leche (1 can = 14 oz)
- 1 cup sour cream
Also
- 8 coffee beans (to add to the piped stars on top)
- 4 cups walnut halves (for adding between the layers and for pressing against the sides of the cake)
Instructions
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Bake the yellow cake: Bake the 2 portions of the Yellow Sponge cake according to directions (the ingredients listed above are for 2 portions). Allow to cool completely.
Then using a long serrated knife (I use this one, then I use these knife fixators to help with making perfectly leveled layers), cut the cakes horizontally into 8 thin layers total. Set the bottoms of 2 cakes aside. They will make up the top and bottom of the finished cake.
Using a cake lifter like this one makes it easy to transfer delicate, thin layers from one place to another.
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Roast nuts: On a baking sheet roast 4 cups of walnuts at 325F for 20 minutes. Toss every 5 min to prevent burning. Allow to cool, then chop into pieces. Sift the chopped nuts through a large-holed sieve to remove the tiny pieces, leaving the larger ones behind. Use the sifted tiny pieces for something else, we won't need them for this recipe.
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Make the syrup: Mix together 1/2 cup sugar, 3 tbsp Bacardi Rum and 1 1/2 cups water for the syrup until the sugar is dissolved. Pour it into a squeeze bottle if available and set aside. Otherwise, you can use a pastry brush or a spoon to soak the cake layers.
How to make the Coffee Cream Filling
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Combine the Cool whip with sour cream: Stir 1 cup of sour cream with ¼ cup of sifted cocoa powder and 2 Tbsp instant coffee or 2 Starbucks Via packet until well combined and smooth. Fold in 8 oz of cool whip and continue folding carefully until the no streaks are seen.
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Whip butter & combine with other ingredients: Whip 12 oz room temperature butter in a stand mixer for about 5-7 minutes or until pale in color and very fluffy, scraping down the sides often. Add 1 1/2 cans of dulce de leche in two additions and whip until combined and fluffy. Carefully fold in the whipped cream.
How to layer the Coffee and Walnut cake
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Reserve cream: Reserve and refrigerate 2 cups of frosting. This will be used for the outside of the cake and decorating.
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Layer the cake: Now, spread a dab of frosting onto the middle of the serving platter. Place one of the bottoms of the split yellow cakes bottom side down on top and press to adhere. Drizzle or brush on some sugar syrup, then add 1/7th of the coffee cream filling and spread into an even layer. Sprinkle with couple tablespoons of the chopped, roasted walnuts. Top with the next cake layer and press firmly to adhere.
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Finish the layering: Continue layering the cake in the manner described above, finishing with the upside-down bottom layer that we reserved earlier. Soak the top with the remaining syrup, then cover the whole cake in a thin layer of the coffee cream using some of the reserved 2 cups from the fridge.
Press the remaining roasted and chopped walnuts all over the sides of the cake.
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Pipe Stars: Now add the remaining coffee cream to a pastry bag fitted with a large star tip and pipe 8 stars around the border of the cake. Add 1 coffee bean inside each piped star. Use any remaining chopped walnuts to sprinkle on the inside perimeter of the piped stars. Refrigerate the cake for 12 hours or overnight before serving.
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Updated June 2020: the recipe was updated to use Cool whip instead of heavy cream as it combines with the buttercream better.
Marina | Let the Baking Begin
Do you use regular or black walnuts in this recipe? I just love the flavor of black walnuts so if not, can I use them in this recipe?
Hi Kim,
to be honest I’ve never even heard of black walnuts so can’t tell you if they’ll work. I use regular walnuts.
Wow! I think I found my new favorite cake, thank you! Sooo good!!
Hi Marina,
Someone mentioned this already but I don’t see a clarification for it. In the recipe notes, under “Tips for Getting the Perfect Coffee Frosting” you mention that heavy cream is the best to use for this cream (as in the refrigerated heavy whipping cream in a carton, usually stands near the milk at the store) but in the recipe card you say Cool Whip (as in the frozen whipped topping in an 8 oz tub found in the frozen section of the store). Which one is best to use for this cream? People mentioned having trouble with the cream so I want to make sure I understand what you mean so my cream can be a success thanks in advance!
Hi Alina,
After more testing I find a more consistent result with Cool Whip, than regular heavy cream. I have changed it in the recipe awhile ago, but the post didn’t reflect that change until now. Make sure to thaw the cool whip before you add it to the cream.
Thank you so much Marina! That’s very helpful 🙂
Made this cake for Thanksgiving this year, and let me tell you it was absolutely incredible!! Everything turned out perfect, but my only confusion with the recipe was whether to use heavy whipping cream or cool whip in the frosting , it mentioned both, so I used cool whip, but I think heavy whipping cream would have been better.
We devoured this cake, will make again!
Hi marina,
The cake looks amazing, can’t wait to try it.
Can you tell me can this frosting be made in advance & kept refrigerated?
Also what is Dulce de leche? I’m from australia not sure it’s available. Can I omit it ? Any thing else I can substitute it with ?
Thanks for sharing
Dulce de leche is a thick caramel flavored milk product made by cooking sweetened condensed milk in its sealed can. You can find specific directions for making it at home if you have access to sweetened condensed milk.
Hi Marina,
This cake looks AMAZING and sounds like a coffee lover’s dream. I have tried to make coffee buttercream once before but it came out quite bitter. My recipe was pretty simple though and it didn’t include dulce de leche, cocoa powder or sour cream so I will definitely give this a try! I love the fact that you have lots of thin layers of cake as well. I wish I could taste some. Thanks for sharing and it was a lovely read! 🙂
Jen Sim Xxx
HI, for the instant coffee do we just put the powder itself or disolve the instant coffee?
Thank you!
Hi Tabita, you just add the powder and it will dissolve in the liquid of the batter.
Hi, Marina,
I love this cake! Thank you for sharing this recipe.
I’ve made this cake twice, and while delicious, the frosting had a little grainy look to it, not texture, just the look. I’m not sure what I’m doing wrong. Maybe over whipping the frosting?
Hi Luda,
Thank you so much!
Yes, just whip the heavy cream a little less next time and that should fix the problem.
I was excited to try this recipe, the sponge cake itself turned out fine, but the frosting recipe didn’t work out for me, three times!! I followed instructions but each time the frosting just wouldn’t come together.. but seeing as how the recipe says to take room temp butter and mix in cold ingredients I don’t see how it would work! Mine was all cuddled and yucky and looked nothing like the pictures! If anyone has tips let me know!
2 question
1) My oven is small, can I bake one pan and then insert the other later. Can the batter wait?
2) The sugar rum syrup, the water should be hot?
I would mix enough batter to bake at once. If you can only bake half the cake recipe, whip it up first, bake it, then proceed with the other half. The cake is very delicate and relies a lot on the fluffiness of the eggs to keep it fluffy. If you just leave it out for half an hour until the first one bakes, most of the air bubbles will pop, which will result a denser second cake.
The only reason to use warm or hot water for the syrup is to help the sugar dissolve. Otherwise it doesn’t matter what temperature water you use.
It says to bake 2 portions of sponge cake according to directions. Where exactly are the directions? What size pan(s)? Oven temp? Length of baking time? Thank you. If I missed the directions somewhere, please forgive!
Hello Halyna,
Just click the words “yellow cake” in pink (it’s a link) and it will take you directly to that recipe.
No comments to read. If i am the first person to bake this i would like to get it right. You have 4 cups ( 16.5 oz) of walnuts in the list of sponge ingredients and 3 cups ( 12.25oz ) of walnuts in the coffee cream ingredients. The instructions only refer to the 3 cups to be roasted and does not mention the 4 cups. BY SHELLED DO YOU MEAN WEIGHT OR VOLUME OF THE NUTS WITH SHELLS ON OR DESHELLED. 28.75OZ SEEMS TO BE A LOT OF NUTS.
Hi guy,
This cake uses 4 cups of halved walnuts in total. I edited the recipe to clarify the type and amount to make it easier to understand.
The 4 cups get roasted, then cooled, chopped, sifted and used for layering the cake and the remnants get used for pressing against the sides of the cake.
You can use less if you’d like, but I think the flavor and the crunch work very well with the flavors.
Thank you for the clarification. if you check the weight of the nuts in the metric page you have left the weight the same as the original three cups and the metric weight now needs to read 473 grammes or 15.8 oz for the four cups you now list.