A gorgeous, dense mud cake base topped with smooth, creamy, easy chocolate mousse. This showstopping chocolate mud cake is covered with a chocolate mirror glaze and is decadence at it’s best.

A closeup of chocolate mousse mud cake with the rest in the background

This indulgent and stunning cake is not your everyday chocolate cake. The mud cake recipe is easy and results in a perfect chocolate mud cake that is then topped with a silky smooth chocolate mousse.  

This post is an update on an old recipe and I’ve not only tested, retested and retested the whole thing, I’ve updated the recipe, post and photos to bring you a gorgeous chocolate mud cake worthy of any celebration. Pinky swear – you can trust me because I made and ate a lot of this.

If you want to make just the mousse without the cake, check out my Eggless Easy Chocolate Mousse.

A chocolate mousse mud cake cut into slices on a black glass plate

This post has quite a lot of steps and photos to help you make this cake perfectly.
I even made a video so you can watch me make it (right above the recipe card).

This showstopper has 3 delectable chocolatey components and each part is totally sublime but together they are the perfect chocolate storm.

  • The rich chocolate mud cake recipe works as a layer cake as well, just double the recipe and use two tins for best results.
  • That chocolate mousse is so luscious and everything you want chocolate mousse to be. Smooth, creamy, light, fluffy, soft and unbelievably melt in the mouth and guess what else? It’s an eggless chocolate mousse.
    While it’s made with dark chocolate, it ends up tasting like milk chocolate once the cream is mixed in. You could use a higher percentage of dark chocolate (this recipe only calls for 50%) however be aware the mousse will set firmer with a higher cocoa percentage chocolate.
  • Then the chocolate mirror glaze on top is totally optional but it finishes the cake with a glorious chocolate shine that feels so special. What a way to spoil your guests.

A slice of chocolate mousse mud cake lifted towards the camera. Whole cake in the background.

What is chocolate mud cake?

Chocolate Mud Cake is a dense, fudgy chocolate cake with a tight crumb. It has an intense chocolate flavour from both the cocoa and melted chocolate in the batter.

Chocolate mud cake is a favourite among cake decorators due to it’s stability making it easy to decorate and stack, plus it carves with perfect straight cuts and no crumbs.

How to make mud cake

Mud cake is very simple to make and is similar to a muffin recipe, in that dry ingredients are mixed in one bowl, wet in another then the two are combined. Since the cake is firm and dense there is no need to cream butter and sugar making it a simple mix and bake cake.

Start by melting together some butter and dark chocolate (not pictured) until you have a smooth, glossy chocolate mixture.

Two bowls for mud cake batter - one with dry ingredients, one with wet ingredients.

In a medium bowl, sift together the dry ingredients (photo 1) then in a separate bowl, whisk together sugar, eggs and milk (photo 2). I use brown sugar in this cake to keep it moist.

Adding melted chocolate to wet ingredients, then adding flour.

Next, add the melted chocolate and butter to the wet ingredients and whisk together (photo 3) then whisk through the dry ingredients until just combined (photo 4).

Pouring cake batter into a cake tin before baking.

Pour the batter into a prepared spring form tin (photos 5&6) then bake the mud cake for around 25 minutes.

*Important step* As soon as the cake comes out of the oven, use a clean tea towel on top and your hand to gently and gradually press the top down until it’s flat. Being a dense cake, it won’t affect the texture but it will give you a nice level surface to spread the mousse on.

For the chocolate mousse layer

Wait until the cake is cool to make the mousse layer. Start by melting together chocolate, butter, cream and sugar (photo 7) until it’s a smooth, glossy ganache (photo 8).

Two bowls - one with whipped cream, the other with chocolate mousse

Let the ganache cool to room temperature before whipping your cream until it holds it’s shape (photo 9) – make sure not to overwhip. Fold the cream into the chocolate mixture in 3 parts (photo 10) until it’s all incorporated.

Folding means to scoop mixture from the bottom of the bowl and fold over the top. This is a method of incorporating 2 sets of ingredients when you want to keep air in them.

In this case, we want to keep the air in the cream as that’s what makes the mousse light and fluffy. Here’s a little video you can watch if you are new to the folding technique. It’s very simple and can be done quickly once you know how to do it properly.

Spreading chocolate mousse out flat in a cake tin

Tip the chocolate mousse mixture out onto the mud cake base and spread it gently with the spoon (photo 11), then level it out on top with an offset spatula (photo 12). Let this set in the fridge for 2-3 hours to make sure the mousse is nice and firm.

*Optional Step* If you want to get perfect straight sides and corners on the mousse, gently heat an offset spatula with hot water (then dry off) or with a kitchen torch and carefully run it along the top and around the sides to flatten any bits that aren’t perfect.

A whole chocolate cake cut into slices sitting on a black glass plate

What is mirror glaze

Mirror glaze is a glossy type of glaze used on cakes that stays shiny once set. There are a number of different ways to make it but most often, cream and sugar are combined (or sometimes condensed milk) with gelatine to make a shiny glaze that sets to soft texture.

This chocolate mirror glaze uses water, gelatine, cream, sugar and cocoa. It sets perfectly smooth and shiny (almost like a chocolate jelly) and is fairly simple to make. If it sets before you use it, you can simply reheat the glaze to melt it again.

How to make mirror glaze

First (not pictured), sprinkle powdered gelatine over water and give it 5 minutes to soften.

The ingredients for mirror glaze in a saucepan, then pouring the glaze through a sieve.

Now, in a saucepan, whisk together some water, cream, sugar and cocoa (photo 13). Heat it over very low heat until combined and the sugar has dissolved. Now add the gelatine and water and mix it through (without simmering) until it’s all dissolved.

Pour the glaze through a strainer into a pouring jug (photo 14) to remove any lumps then place the glaze in the fridge or freezer to cool completely before pouring it over the mousse layer.

How to mirror glaze the cake

The glaze needs to be cool enough that it has thickened but not so thick that it can’t be poured. Once it coats a spoon thickly without all running off, you know it’s ready. It will begin to set as soon as you pour it over the cake. The glaze doesn’t need to be very cold as it will set if it’s too cold, due to the gelatine.

Mousse mud cake sitting over a bowl ready to catch glaze drips

Set up a large platter or dish with high sides, with a flat bottomed dish or similar upturned on the base (photo 15). Remove the sides from the springform tin but leave the cake on the metal base. Sit this on top of the upturned dish (photo 16).

Pouring chocolate mirror glaze onto a cake, then spreading it out.

Now pour the chocolate mirror glaze over the cake, moving the jug around so the glaze runs down the sides (photo 17). Use a large flat metal spatula to smooth it out (photo 18).

This bit gets a bit messy. Move the cake to the side and tip the overflowed glaze back into the jug and repeat until all the glaze is used up.

Planning ahead and storage!

This cake does take a little time and effort but it’s so worth your time. The chocolate mud cake recipe is super simple and quick, but you will need to allow quite a bit of waiting time in cooling and setting for both the chocolate mousse and the chocolate mirror glaze.

The mousse will take around 2-3 hours to be firm enough to pour the glaze over the top. The glaze will take around 45 minutes to become cool enough to pour then another 45 minutes to an hour to set. So you see there is around 4.5-5 hours just in setting and cooling.

For these reasons, I recommend making this cake the day before. It will keep well for up to 4-5 days after that in the fridge, stored in an airtight container.

Click here to Pin this recipe for later!

A slice of chocolate mousse mud cake laying on its side on a black plate

This is such a luscious and special cake to make for your guests. A total showstopper, this Chocolate Mousse Mud Cake will have them coming back for more – my trusty taste testers all agree.

A closeup of chocolate mousse mud cake with the rest in the background

Chocolate Mousse Mud Cake

4.74 from 34 votes
A gorgeous, dense mud cake base topped with smooth, creamy, easy chocolate mousse. This showstopping chocolate mud cake is covered with a chocolate mirror glaze and is decadence at it’s best.

Ingredients

FOR THE CHOCOLATE MUD CAKE

  • 113 g unsalted butter (1 stick / 1/2 cup)
  • 75 dark (70%) chocolate (2.6oz)
  • 85 plain (all-purp) flour (2/3 cup / 3oz)
  • 20 g cocoa (2 tablespoons / 0.7oz) (notes)
  • 1/2 teaspoon  baking powder
  • 1/4  teaspoon  salt
  • 1/2 cup / packed  light brown sugar (100g / 3.5oz)
  • 1/3 cup white granulated sugar (65g / 2.3oz)
  • 2 teaspoons instant coffee
  • 2 tablespoons hot water (notes)
  • 1/4 cup milk
  • 1 large egg
  • 1 teaspoon  vanilla extract

FOR THE CHOCOLATE MOUSSE

  • 2 1/2  cups  whipping cream, divided
  • 200 (7oz) dark (50%) chocolate
  • 57 g (1/2 stick / 1/4 cup) unsalted butter
  • 2 tablespoons icing sugar (notes)

CHOCOLATE GLAZE (OPTIONAL)

Instructions
 

FOR THE CHOCOLATE MUD CAKE

  • Grease and line a 9 inch / 22cm round springform tin with baking paper. Preheat the oven to 180C / 350F / 160C fan forced.
  • Combine the butter and chocolate in a saucepan over low heat and stir until everything is melted and you have a smooth liquid. Allow to cool for a few minutes.
  • In a medium bowl, sift together the flour, cocoa, baking powder and salt. Add both sugars and whisk together until there are no lumps.
  • Combine the hot water and coffee and mix to dissolve.
  • In a large bowl, whisk together the cooled chocolate and butter mixture, eggs, coffee, milk and vanilla until well combined.
  • Add the wet ingredients to the dry ingredients and stir until just combined.
  • Pour the batter into the prepared tin and bake for around 25-28 minutes, until a toothpick inserted comes out with just a crumb or two attached.
  • Using a clean tea towel, very gently press down all over the top of the cake to flatten out any dome and press out a little to the edges to make sure the sides of the cake are right up against the tin. This step is optional but it will give your cake nice straight layers. Leave it in the tin to cool.

FOR THE CHOCOLATE MOUSSE (only once the cake has cooled)

  • Pour 1/2 cup cream into a small saucepan and the remaining cream into a glass bowl and place in the fridge.
  • Heat the 1/2 cup of cream, chocolate, butter and sugar over very low heat and stir until almost everything is melted. Remove from heat as soon as just a few lumps are left and stir until you have a smooth ganache. Pour it straight into a glass bowl and let it cool to room temperature.
  • Once the ganache has cooled, beat the remaining 2 cups cream to soft peaks. Using a spatula, stir about 1/2 cup of the whipped cream straight through the ganache to lighten it. Now fold the remaining cream, in two parts, into the mousse until just mixed through. Be very careful not to overmix the mousse or you'll knock the air out, making it dense.
  • Spread the mousse over the cake base, then smooth out the top with an offset spatula. Chill 2-3 hours.

FOR THE CHOCOLATE MIRROR GLAZE (this can take up to an hour to cool to the right consistency).

  • Sprinkle the gelatine over ¼ cup of water and allow it to ‘bloom’ for 5 minutes while you get on with the rest.
  • Combine the other ¼ cup of water, the cream, sugar and cocoa in a saucepan over low heat. Whisk to combine then use a spatula to stir over low heat, until the sugar has dissolved completely. Keep the heat low, it must not come to a boil.
  • Add the gelatine and water mixture and whisk in thoroughly.
  • Pour the glaze through a sieve into a jug (to remove any lumps). Now place the jug in the fridge or even the freezer until it cools enough to coat a metal spoon without running straight off. If there is a light film or skin on the top of the glaze, make sure to skim that off with a spoon before using.
  • Remove the outer frame of the spring form tin and the baking paper carefully. Optional extra step: If you want to smooth the mousse out a little around the sides and top see the notes section.
  • With the cake still on the baking tin base, sit it on top of a flat bowl inside a larger flat bowl or plate with high sides. Pour the glaze over the cake and use a large flat metal spatula to smooth it and push it over the edges, being careful not to press into the mousse. Remove the cake to drain the bowl back into the jug and repeat a second or even third time.
  • Leave the cake in the fridge to set for at least an hour before carefully removing the base. The tin base should come away fairly easily, then holding the cake underneath with one hand, use the other to peel back the baking paper halfway. Swap hands and remove the paper entirely. Use a sharp knife to run around the bottom edge to tidy up where the set glaze is not straight. Transfer to a cake plate and serve.

Video

Notes

  1. Cocoa & hot water: I use a standard Australian 20ml tablespoon (1 Tbsp = 4 tsp)
  2. This cake should be served straight from the fridge.
  3. I recommend making this cake a day ahead due to a number of cooling and setting times.
  4. Baking time: This will depend on your oven, check it as you get close to the suggested time.
  5. Feel free to use darker chocolate for the mousse, but be aware it will set to a firm consistency.
  6. If you want to smooth the mousse out a little around the sides and top, heat an offset spatula either by running under hot water, then drying it off or use a kitchen blowtorch. Very gently run the heated spatula over the mousse to smooth it.
  7. The glaze can take up to an hour to cool down enough to pour over the cake. Once it coats a spoon thickly, without all running off, the glaze is ready. It does not need to be very cold.
  8. Once cold, the glaze will turn into a chocolate jelly. This can simply be reheated in the microwave to get it back to pouring consistency again if needed.
  9. If you'd like to add the gold drizzle like this one, just mix a little edible gold glitter with melted white chocolate and drizzle over the top.
  10. This cake will keep for 4-5 days in the fridge, in an airtight container.
  11. Changes to the video: Due to requests for a moister cake, this recipe has been updated. Slight changes to the video include adding coffee and one less egg. White sugar has also been added and some quantities have changed. The sugar is now mixed with the dry ingredients. Video will be updated in the near future.

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