The ultimate moist chocolate walnut cake. This decadent chocolate cake is topped with dark chocolate ganache frosting and packed with walnuts!
Ingredients for Chocolate Cake with Walnuts
For this cake you'll need:
- Butter - unsalted, room temperature butter.
- Sugar - either caster sugar or superfine granulated sugar.
- Crème fraîche - if you can't find crème fraîche, you can substitute with mascarpone, soured cream or even spreadable cream cheese.
- Water - hot, freshly boiled water.
- Cocoa powder - a good quality cocoa powder will help ensure a rich chocolate flavour.
- Instant coffee granules - coffee helps to accentuate the flavour of chocolate, so your cake will not taste like coffee, it will just be a deeper chocolate. If you don't have instant coffee available, you can also just replace the amount of water with filter coffee or espresso. The stronger the coffee brew, the deeper the chocolate flavour.
- Vanilla extract
- Flour - either all purpose flour or plain flour will work in this recipe.
- Baking soda
- Walnuts - shelled and chopped. If you like bits of baked walnut in your brownies, you'll like these roughly chopped in the cake. If you're not a major fan of the added texture, chop these up fine and they'll add the flavour without bits.
For the frosting, you need a couple of extra ingredients:
- Chocolate - good quality dark chocolate, finely chopped or in small chips.
- Cream - either heavy whipping cream or double cream.
- Walnuts - a handful or so of roughly chopped, shelled walnuts for decoration.
How to Make Chocolate Walnut Cake
Making this cake requires a few simple steps:
1. Blooming Cocoa
After standard preparations, like preheating the oven and lining a cake tin, your first step for this coffee walnut cake recipe is to bloom the cocoa.
What is blooming cocoa, you might ask? Well, blooming cocoa is the process of dissolving cocoa powder into warm water. This often takes the form of making a paste. This is done in order to accentuate the chocolate flavour for your recipe.
For this recipe, simply mix recently boiled, warm water with the instant coffee granules and cocoa powder - this will smell a lot like a strong mocha!
You could also use fresh made warm filter coffee or espresso for the water, instead of instant coffee granules.
2. Mix Wet Ingredients
Once you've mixed together the cocoa, coffee and water, add the vanilla to this and set aside while you cream together the sugar and butter.
There is a high ratio of sugar to butter in this recipe, so it will take a little longer than you might expect to blend the two. Cream for a couple of minutes until light and fluffy, then add the egg and beat to incorporate.
Next add the crème fraîche and cocoa coffee mixture and whisk to combine.
3. Adding Dry Ingredients
When you have your liquid batter, it is time to add the dry. Reserving a teaspoon or two of flour, sift the rest, along with the baking soda and salt, into the batter. Stir together with a spatula until just combined.
Add the reserved teaspoon of flour to the chopped walnuts - this will help the walnuts distribute in the batter. Then add this to the batter, stir to combine, and pour into a baking tin.
Note on Chopped Walnuts in Cake Batter
I'll be honest, if you use large roughly chopped nuts in this recipe, most will probably sink towards the bottom - this is because they're heavy in a very wet batter. I still like the added crunch so would recommend using rough chopped bits. But if a more even distribution is particularly important, go with a finer chop. In either case, coating in a bit of flour before mixing should help.
Ganache is incredibly easy to make. Simply heat cream until just about to boil (simmer for a couple minutes to ensure it is well warmed through) and pour over chopped chocolate.
Conventionally, if using weights, it is equal parts chocolate to cream (so for example 50g chocolate to 50mL heavy whipping cream). But, you don't need metric for this ratio.
Typically, my ganaches are 2oz chocolate per ¼ cup cream. For this ganache, I recommend 5oz dark chocolate (chopped or in chip form) with ¾ cup heavy cream. This slightly higher ratio of cream helps create a glossy, spreadable frosting.
A couple of ganache tips:
- Leave the chopped chocolate to soak in the warm cream for about 2 minutes before stirring. Leaving it to sit helps the chocolate to warm up and makes it melt more easily and smoothly.
- If your chocolate doesn't all melt down as you stir and you're left with lumps, don't panic! Simply place the heat proof bowl over a pan of simmering water. Essentially make a DIY double boiler. This will rewarm the cream and help melt the chocolate down gently. This shouldn't effect the shine of the ganache.
- Ganaching a cake helps to prevent it from drying out or going stale. Coat the top and sides in a thin layer before adding the remaining ganache to the top. By covering all sides, even in just a thin layer, your cake will stay fresh for longer.
This walnut and chocolate cake will stay fresh for several days coated in ganache. The ganache helps form a protective layer which will prevent the cake from drying out while also giving it a decadent chocolatey finish.
Strictly speaking, ganached cakes are best kept in the fridge, as the frosting is cream based. This is the safest way to store it, especially if you are making the cake in advance or if your kitchen is quite warm. Ganache will harden in the fridge, so before serving, remove from the refrigerator and allow to come to room temperature so that the ganache is able to soften.
You can also leave the cake at room temperature for a couple of days without issue, but keep in a cool place.
Yes! Ganached cakes actually freeze quite well and will keep for up to a month. Before freezing, place the cake in the refrigerator to allow the ganache to set hard. Then wrap this well in cling film, followed by a layer of aluminium foil and freeze.
Absolutely - this recipe can be made in a variety of different types of tins. The measurements and timings have been developed for a 7" round cake pan, however, you can certainly use other shapes and sizes.
Be aware that timings for different pan shapes will vary, so keep an eye on the oven and check with a toothpick to determine doneness.
If you like this recipe, check out some other decadent chocolate creations:
- Chocolate Orange Cupcakes
- Chocolate Battenberg Cake
- Texas Sheet Cake
- Seven Layer Chocolate Cake
- Cookie Bottomed Brownies
Chocolate Walnut Cake
- 7.5 inch round cake pan I recommend using silicone cake tins for ease, but you could use traditional cake pans, lined with grease proof paper. This recipe will work fine in 7" or 8" round tins or in similar sized square tins. Other sizes can be used, but baking times will vary.
- large mixing bowl
- hand held electric beater
Ingredients for Cake
- 2 tablespoon cocoa powder
- 1 tablespoon instant coffee granules see note for alternatives
- ¼ cup water warm, recently boiled
- ½ teaspoon vanilla extract
- ½ cup butter unsalted, softened to room temperature
- 1 cup superfine granulated sugar or caster sugar
- 1 egg
- ¼ cup crème fraîche or mascarpone cream
- 1 cup all purpose flour or plain flour
- ½ teaspoon baking soda
- ¼ teaspoon salt
- ¾ cup roughly chopped walnuts plus extra for decorating
Ingredients for Ganache Frosting
- 5 oz dark chocolate finely chopped or in chips
- ¾ cup heavy whipping cream or double cream
- Begin by preheating your oven to 350°F (175C/155C Fan) and preparing your cake pan. (see notes)
- In a small bowl, mix the hot water with the instant coffee granules until dissolved, then add the cocoa powder. Stir until this is also dissolved then add the vanilla extract. Set this aside.
- Place the sugar and butter in a large mixing bowl and beat with a handheld electric whisk until light and fluffy. This will take about 3 minutes.
- Add the egg and beat to incorporate. Then add the crème fraîche and coffee cocoa mixture. Whisk until smooth.
- Reserve a couple of teaspoons of the flour and sift the rest into the batter along with the baking soda and salt. Stir with a spatula until just combined.
- Using the reserved flour, coat the chopped walnuts and then add to the batter and fold to distribute.
- Pour the chocolate walnut cake batter into the prepared cake tin and spread evenly. Bake in the centre of the preheated oven for about 1 hour, checking occasionally after about 45 minutes. The cake is done when a toothpick inserted in the centre comes out clean.
- Once baked, remove from the oven and allow to cool for a few minutes in the cake pan before turning out to cool on a wire rack for at least 30 minutes before frosting.
- After allowing the cake to cool, make the ganache. Heat the cream in a saucepan until simmering. Allow this to simmer for a couple of minutes until it is just about boiling. Then remove from the heat and pour over chopped chocolate or chocolate chips in a heat proof bowl. Let this sit for two minutes before stirring until smooth.
- Frost the top and sides of the cake in a thin layer or ganache and then add the remaining ganache to the top to create a thick rich chocolatey topping. Decorate with chopped walnuts or walnut halves.