This decadent chocolate mud cake is incredibly moist and fudgy with a thick layer of chocolate ganache on top. It’s beautiful in its simplicity but is surprisingly simple to make. Made with dark chocolate – it’s the perfect cake for true chocolate lovers!
The Perfect Chocolate Mud Cake
There’s something incredibly satisfying about a slice of rich, dense chocolate mud cake. This recipe doesn’t take much more effort than using cake mix, but it looks truly impressive and rivals any bake shop. I made it in a single layer, but it can be easily adapted to a double layer cake if you choose.
Since moving to Australia, I realized everyone was slightly obsessed with mud cakes. I think they must be the most purchased item at Woolworths. But what’s not to love about a mud cake?
What’s a Mud Cake?
For my non-Aussie readers – the type of mud cake I’m referring to (not to be confused with a Mississippi mud cake) has:
- a moist and fudgy texture
- a tight cake crumb, to give the cake a dense and decadent feeling – as opposed to a light and airy cake
- a single layer that’s extremely tall
- chocolate ganache on top – but you could also use chocolate frosting or leave it plain
This recipe is made with both dark chocolate and cocoa powder for a rich, complex chocolate flavor. I also love to add in a little instant coffee powder (or instant espresso powder). You don’t actually taste the coffee, but it helps to enhance the chocolate flavor.
My secret to a super moist mud cake is adding sour cream. It makes the cake extremely moist, and extends the shelf life as well.
Note: You will need a very big bowl for making the cake batter!
Bake Times & Pan Sizes
I baked my mud cake in an 20 cm (8-inch) round cake pan with 10 cm (4 inch) sides. The secret to baking mud cakes (or any really tall cake) is that you need to go low and slow. Mine baked for approximately 1 hour and 30 minutes at 150C in a fan forced oven (300F in a convection oven, or 325F in a traditional oven). In a 23 cm (9-inch) tin, I’d expect the bake time to be around 1 hour to 1 hour and 15 minutes.
For a double layer cake you can bake in in the same the pan in a 20 cm tin with 10 cm sides, as I did. Then once the cake is fully cooled slice, slice it in half. Alternatively, you can bake the cake in two 20-cm tins with 5 cm sides for approximately 30-40 minutes, at the same temperature.
Pro Tip: I always use a loose bottom cake pan for mud cakes so that it’s easy to remove from the pan. Line the bottom of the cake pan with baking paper, then line the sides with a strip of baking paper as well. Because the cake is very dense, if you skip these steps it can be hard to remove from the pan. You can see what I mean below. 
Serving & Icing Alternatives
I topped my cake with a layer of chocolate ganache, as outlined in the recipe below. Because the cake is very rich – I prefer ganache over frosting or icing because it’s less sweet. Other delicious options would be:
- Skip the ganache and sift a little icing sugar on top once the cake has fully cooled. Serve with a scoop of ice cream, or whipped cream and berries.
- For a double layer cake, double the ganache recipe and add a layer of ganache between the 2 cake layers and on top. Leave the sides bare.
- For a double layer cake, add a layer of whipped cream in the middle and ganache on top.
- For something very rich and sweet – frost the cake with chocolate buttercream. This is my favorite recipe: chocolate buttercream frosting. Divide the recipe in half to frost just the top of a single layer cake. Or multiply the recipe by 1.5 to frost the middle, sides and top of a double layer cake.
Decorating Tip: After the cake is fully cooled, use a serrated knife to gently saw off the rounded top of the cake before adding ganache or frosting. If you’re leaving the cake plain, you can skip this step.
A Note About Chocolate Ganache:Â If you want the ganache to drip over the sides, pour the ganache over the cooled cake immediately after making the ganache. If you want a thick layer on top (as pictured), pop the ganache in the fridge for 20-30 minutes, then spread it over the cooled cake.
More Chocolate Cake Recipes to Love:
- Chocolate Layer Cake – this is a traditional American style birthday cake
- Double Chocolate Cupcakes
- Chocolate Mug Cake – for when you need a single serving, late-night treat
Chocolate Mud Cake
Equipment
- 20 cm loose-bottom cake pan with 10 cm sides (see recipe notes for pan alternatives)
Ingredients
Chocolate Mud Cake
- ¾ cup unsalted butter (170 grams)
- 7 ounces dark chocolate (200 grams) finely chopped
- 2 teaspoons instant coffee powder or 1 teaspoon instant espresso powder
- 1 cup hot water (240 ml)
- 2 cups all-purpose flour (250 grams) AKA plain flour
- â…“ cup cocoa powder (30 grams)
- 1 ¾ cup granulated sugar (350 grams) AKA caster sugar
- 1 teaspoon baking soda
- 1 teaspoon baking powder
- ½ teaspoon salt
- 2 large eggs
- 2 teaspoons vanilla extract
- 1 cup sour cream (240 ml) from the tub (I used 18% MF)
Chocolate Ganache
- 8 ounces dark chocolate (226 grams) I used 50%
- ¾ cup whipping cream (180 ml)
Instructions
Chocolate Mud Cake
- Preheat the oven to 150C fan forced (300F convection bake) or 160C (325F) in a conventional oven.
- Using a 20 cm (8 inch) loose-bottom cake pan with 10 cm (4 inch) sides, line the bottom of the pan with parchment paper. Then line the sides with a strip of baking paper.
- Add the butter, chocolate, water and instant coffee powder to a large saucepan over low heat. Melt everything together and gently stir until smooth and melted.
- Remove from the heat and pour the mixture into a very large bowl. Let cool slightly.
- In a separate bowl whisk together the flour, cocoa powder, sugar, baking soda, baking powder and salt.
- Once the chocolate mixture is no longer very hot (it can still be slightly warm), whisk in the eggs. Then stir in the sour cream and vanilla extract until smooth.
- Stir the dry ingredients into the wet ingredients. Whisk the mixture until smooth. You can use an electric mixer if you prefer.
- Pour the batter into the prepared pan.
- Bake in the preheated oven for about 75 - 90 minutes, or until an inserted toothpick comes out clean or with a few damp crumbs. If you gently press the top of the cake with your finger, it shouldn't move. Or if you gently nudge the pan, the cake shouldn't wobble.
- Cool the cake in the pan for at least 30 minutes, then turn the cake out and continue cooling on a wire rack.
Chocolate Ganache & Decorating
- Once the cake is fully cooled, optionally, use a serrated knife to gently saw off the rounded top.
- Chop the chocolate into very fine pieces and place in a heat-proof bowl.
- Heat the cream until almost boiling.
- Pour the hot cream over the chopped chocolate and let sit for 3-5 minutes. Then whisk until smooth. If the chocolate hasn't quite melted, microwave on medium power (about 500 watts) for 30 seconds.
- Optionally, pour the ganache over the the cake and let it drip over the sides. Or let the ganache cool for about 30 minutes, then spread it over the top of the cake.
Notes
- This recipe can also be baked in a 23 cm (9 inch) pan with 6 cm (2.5 inch) sides. The bake time will be 60-75 minutes at the same temperature.
- I used 70% dark chocolate for the cake and 50% dark chocolate for the ganache. I do not recommend using anything stronger than 70% for the cake, or it can be too bitter. Using 50% dark chocolate in the cake will result in a slightly sweeter cake.
- Store cake covered in an airtight container at room temperature for up to 3 days, or in the fridge for up to 5 days.
- Nutrition information is an estimate only and based on 1 slice with ganache, assuming that the cake is sliced into 10 equal pieces. Each piece will be very rich - so you could probably get 12 pieces from this recipe.Â
Hi there, I do not see the instant coffee powder that is listed in the ingredients anywhere in the instructions. I am wondering if it mixed with the butter, chocolate, and water in step 3? Thanks
Thank you so much for that catch – I’ve just updated the recipe. And yes, you’ll add the instant coffee powder with the butter, chocolate and water.
Hey I can’t find sour cream where I live so is there anything I can substitute it with? It seems a really interesting recipe and I can’t wait to try it . I’ve also done your vanilla mug cake ,which was also awesome 👌
I think plain Greek yogurt would be fine 🙂