Chocolate Ganache Cake Recipe

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If you are looking for the ultimate chocolate ganache cake with an oil based sponge, you are in the right place. This easy to make two-layer chocolate cake is rich, moist and deeply chocolatey with a rich and silky smooth chocolate ganache frosting.

This cake is the perfect celebration cake, birthday cake, chocolate cake and bake for the weekend. The sponge is super light and moist, and is a crowd pleaser for everyone.

Notes from The Patisserie

I love baking any form of cake, and having published over 100 cake recipes in my time now, it’s a firm favourite task of mine. I have many a chocolate sponge, but this one?! It’s new, and it’s indulgent, and it’s EASY to make.

The secret to this wonderfully soft chocolate is blooming the cocoa powder in water before adding to the batter – it helps create a richer and more intense chocolate flavour, without having to use actual chocolate in the sponge as well as the ganache.

I wanted to create a two layer cake as it’s the most popular choice, but you can easily increase the recipe by another half to create three layers, and bake into three tins, or you can half the recipe, and bake into one tin, for a single layer sponge.

Oil based vs butter based

For this recipe, I have chosen to use an oil based sponge as it was very highly requested on my blog, but also the moisture it brings is hard to beat. As oil is liquid at room temperature it helps create a softer and more moist texture for a sponge, whereas butter often firms up again to create a more solid texture.

Neither method is better or worse, they are just different styles of sponges. If you want to make a chocolate fudge cake sponge instead, that’s great. And you can also make a basic chocolate cake for this sponge instead as well.

For this particular chocolate ganache cake recipe, the oil works wonderfully alongside the bloomed cocoa powder, and buttermilk, to create a soft, moist chocolate sponge that everyone will love.

Ingredient notes and tips for the perfect sponge

The list of ingredients for the sponge is quite comprehensive, but all of the ingredients play an important role. Of course, find all of the recipe and method below in the recipe card

Cocoa powder – I always recommend using a pure and rich cocoa powder, and not a cheap/hot chocolate powder. The higher the cocoa content in the cocoa powder the better.
Flour – I use self raising flour as I want the natural rise in the flour to help the cake, and it helps create the better texture. You can use plain flour instead, but you need to add extra baking powder (1.5tsps worth)
Sugar – I love to use light brown soft sugar because it carries the natural molasses flavour and has a caramel undertone, but you can use golden caster sugar or even regular caster sugar
Raising agents – A little touch of baking powder helps combat the other ingredients that could potentially cause a denser texture
Salt – optional, but helps create a delicious balance of flavour
Flavours – I love to add vanilla extract to almost everything, but it is optional.
Oil – I would recommend using a vegetable oil, or sunflower oil, as they are flavourless. You can use olive oil, but try to use a lighter flavoured one so it doesn’t impact the overall flavour too much.
Eggs – I use three medium eggs, if you have large, I would recommend using two large and an extra egg yolk.
Buttermilk – This is part of the reason why the texture of this sponge is so wonderful. Recommendations for making your own below in the FAQS

How to make the best ganache

I decided to use a really good core ganache for this recipe, and use dark chocolate as the main base. I find this the most consistent flavour and base for decoration, and it tastes really chocolatey.

As a rule, I would always recommend using dark chocolate that is 70% cocoa content, or higher. I do not use a confectionary brand of chocolate for this, I just use basic chocolate or cooking chocolate that has the correct cocoa percentage.

To make the best ganache, I would recommend finely chopping the dark chocolate first, or use small callets that don’t need chopping. Ideally, you need to mix the ganache as little as possible once the cream has been added.

I heat my cream in a pan, on the hob, until just before boiling point. It will be steaming, but you don’t want it to boil as that is going to be too hot – pour this over the dark chocolate, and do not stir for five minutes. This will allow the chocolate to melt. Once those five minutes is up, you can stir to melt and create your ganache.

Making a milk chocolate ganache

I know that some people do not like dark chocolate, and that is totally okay. As cocoa content is so important when it comes to ganache, to make a milk chocolate ganache, you will need:

310g milk chocolate
240ml double cream

I would recommend using supermarket own or baking chocolate, I would avoid using brands. The cocoa content for milk chocolate would ideally be: 25-35%

Making a white chocolate ganache

As white chocolate is so much lighter in cocoa content due to not containing cocoa solids, the ratio for chocolate to cream is much higher typically, so you will need:

383g white chocolate
167ml double cream

Again, I would avoid brands, and use supermarket own or baking chocolate. Both of these ratios are designed to have the same quantity of ganache overall to decorate the cake with.

FAQs

I don’t have any buttermilk, what can I use instead?

Add 225ml whole milk (or other milk) and 1tbsp lemon juice or vinegar to a bowl. Whisk together, and then leave to sit for 5 minutes before using

My ganache split what can I do?

You can add in 1tbsp warm milk or cream (or 1tbsp of boiling water), and use an immersion blender or whisk to whip it back together. If it splits again whilst decorating, repeat the process with a vigorous whisk

Can I use butter in the sponge instead of oil?

Yes, you can – use 175g butter – beat it together with the sugar and then add the rest of the ingredients as per the method.

Will my ganache stay soft or will it set?

The extra amount of cream (typically ganache is equal parts) or 50ml is designed to keep the ganache slightly soft to allow it to cut well and not fully set solid. However, you can add 50g of butter to make it more luxurious and even less likely to set solid

Can I flavour this in any way?

Definitely! You can add 1-2 tsp of any extract you want such as orange, or mint. You can also add in espresso powder for coffee flavour

A soft moist chocolate sponge cake with a dark chocolate ganache topping and middle

Print Pin Rate

Category: Cake

Type: Cake

Keyword: Chocolate, ganache

Prep Time: 45

Cook Time: 45

Cooling Decorating: 2

Total Time: 3 30

Servings: slices

Author: Jane’s Patisserie

Ingredients

Sponge

75 g cocoa powder
175 ml boiling water
3 medium eggs
125 ml vegetable/sunflower oil
1 tsp vanilla extract
200 g self raising flour
300 g light brown soft sugar
1 tsp baking powder
0.5 tsp sea salt
225 ml buttermilk (see blog about making your own)

Ganache

250 g dark chocolate
300 ml double cream

Grams – Ounces

Instructions

Sponge

Add the cocoa powder and water to a bowl and mix to combine – leave to cool for 10 minutes
Preheat the oven to 170ºc/150ºc fan and line two deep 8” cake tins
Add the oil, eggs, and vanilla to a large bowl and whisk to combine
Add the cocoa/water mix and stir through
Add the flour, sugar, baking powder and salt and mix again
Add the buttermilk and stir to combine
Split between two lined tins and bake for 40-45 minutes or until baked through
Leave to cool fully in the tin

Ganache

Whilst the cake is cooling make the ganache
Add finely chopped or small pieces of chocolate to a bowl
In a pan, heat the cream until steaming and before boiling
Pour over the chocolate and leave to sit without stirring for 5 minutes
Stir to combine and smooth
Add the first sponge to a plate and add on some of the ganache
Add the second sponge on top, and smooth the ganache around the sides and top

Notes

This cake will last for 3-4 days at room temperature on a cool day, or in the fridge on a hot day (this will firm the cake up slightly)
This cake will freeze for 3+ months
I use two of these 8″ tins for my cake

Storage and Freezing

As the cream has been heat treated in making the ganache, the cake can last for 3-4 days at room temperature in a cool place. I would use a cake box or large cake tin to store it in. It can store in the fridge, but that will firm up the ganache and sponge slightly

This cake can freeze for 3+ months. You can wrap the sponges and freeze them on their own, or you can freeze the whole cake.

Related recipes

I adore this recipe, but I have lots of other chocolate recipes that you can check out:

Ferrero Rocher drip cake – If you want a fancy and out of this world celebration style drip cake, this cake is for you. With a hazelnut Ferrero rocher twist, it’s luxurious and delicious
Chocolate drip cake – A basic sponge cake, with a celebratory decoration style
Chocolate fudge loaf cake – a moist, soft and delicious fudge cake in loaf form, with a smooth luxurious chocolate fudge frosting