Fudgy Vegan Brownie Cake – Easy!

This triple-layer vegan brownie cake is so fudgy and moist with chocolate buttercream frosting! It’s a simple yet incredibly indulgent dessert that everyone will love. It’s perfect for birthday parties and festive events like Thanksgiving and Christmas!

*This post may contain affiliate links. For full disclosure visit our Affiliate Disclosure page.

Fudgy brownies in a cake with rich and smooth chocolate buttercream frosting? Count me in! I made this incredibly decadent and indulgent fudgy brownie cake and I love it so much I need to share it with everyone. It’s a triple-layer cake but trust me it’s easy and simple to make for beginners. This vegan brownie cake is perfect for home parties, birthday parties, and festive occasions too. Chocolate lover’s ultimate dessert!

Main ingredients and substitutions

Plain flour: I used regular plain flour for this recipe. You can use a 1:1 gluten-free flour too if you want to make it GF.

Cacao powder: Cacao powder is made 100% from cacao. Be careful not to confuse it with cocoa powder. Coca powder has added sugar and other ingredients so if you use cocoa powder the taste of the final product will be different. You can use 100% pure carob powder if you want which has a similar taste to chocolate but I prefer the flavour of cacao powder.

Vegan milk chocolate: I used milk chocolate in this recipe. It creates such a lovely fudgy texture in the cake! You can also use dark chocolate if you prefer a less sweet taste.

Vegan butter: I love using Naturli’s vegan butter for baking! You can try making the cake with vegetable oil instead of vegan butter. The texture of the cake will be slightly different and a little more oily if using vegetable oil. I used the same vegan butter for the chocolate buttercream frosting too, it turns out amazing every time!

Brown sugar: I used brown sugar to make a soft and moist texture in the cake. You can also use other types of sugar too such as caster, granulated, coconut, etc.

Instant coffee powder + water: I used it to enhance the chocolate flavour and it works great in chocolate recipes! If you are sensitive to caffeine skip the coffee powder and swap the water with plant milk.

Soy milk: Feel free to use any other plant milk of your choice too such as almond, oat, rice, etc.

Other ingredients: icing sugar, soy whipping cream, apple cider vinegar, and baking powder.

*I use bone char-free sugars for all of my recipes. I cover the topic in my article Vegan Baking 101. Go to the “Is sugar vegan?” section to learn more!

Recommended equipment for this recipe

18cm(7inch) Cake Tin: I used a 18cm(7in) cake tin. You can use square one if the size is the same or similar.

Electric mixer: Use a stand mixer or hand mixer to make the buttercream frosting.

Cake stand and spatula

Parchment paper: Lining the cake tin with parchment paper makes it easier to remove the cake.

*The ingredient list and measurement for this recipe can be found in the recipe card at the bottom.

How to make fudgy brownie cake

Step 1: Prepare wet ingredients

Preheat the oven to 180°C(350°F).

Let’s prepare wet ingredients for the cake! First, mix the soy milk and apple cider vinegar in a jug or medium bowl to make vegan buttermilk. Set aside for it to curdle. In a small bowl, mix the instant coffee powder and hot water until the coffee is dissolved completely. Set aside.

Step 2: Mix wet ingredients

In a medium-size saucepan, melt the vegan butter and vegan milk chocolate together until they are melted and well combined. It should look nice and silky. Add the vegan buttermilk and coffee mixture to the saucepan and mix thoroughly until well combined. That’s wet ingredients all mixed and combined!

Step 3: Mix the dry ingredients and make butter

In a large mixing bowl, combine the plain flour, cacao powder, brown sugar, and baking powder and mix until they are well combined. Pour the wet mixture into the dry mixture and mix gently with a large wooden spoon or a silicone spatula until just combined. It’s ok to have tiny lumps a little bit, they’ll incorporate in the oven! What’s important here is not to over-mix the batter. Over-mixing causes a touch and rubbery texture in the cake.

Step 4: Bake

Pour the cake batter into 3 lined cake tins evenly and smooth out the top. Bake in the preheated oven for 18 mins. 18 mins is the perfect length of time for my oven but it may be different for your oven. To check if the cake is done, do a toothpick test.

Insert a toothpick in the centre of the cake and if it comes out with wet batter, bake for another 3-5 mins. The toothpick should come out with a moist cake crumb when it’s ready. Be careful not to overbake! If the toothpick comes out completely clean, it might be a sign that you overbaked. 

Once the cakes are done, rest them on a countertop until they are at room temperature or slightly warmer than room temperature. Take them out of the tins and transfer the cakes onto a cooling rack and cool them completely while making the chocolate buttercream frosting.

Step 5: Make the chocolate buttercream frosting

With a stand mixer or hand mixer, beat the vegan butter until creamy and fluffy about 2-3 mins with a balloon attachment. Add the soy whipping cream and whip further for about 2-3 mins. At this point, the mixture should be creamy, fluffy, and paler in colour. Add the cacao powder and icing sugar 1 cup at a time and mix until very well combined.

Add in the melted vegan milk chocolate and whip until everything is well combined. The buttercream frosting should be creamy, smooth, and fluffy! 

Step 6: Assembly

Once the cakes are completely cooled down, place the first layer on a cake stand. Place the chocolate buttercream frosting on top and spread evenly. Place the second layer and repeat until the third layer.

Cover the side with buttercream frosting and smooth out with a cake-decorating spatula or normal spatula. I used a small tapping movement to make the pattern on the cake! Slice and enjoy.!

Serving tips and ideas

• Serve a slice with some fresh berries like strawberries, raspberries, blueberries, and blackberries.
• Whip up some vegan cream and top it on a slice. Mmm, delicious.
• Sprinkle some shaved vegan chocolate or melted chocolate for more chocolatiness!

Expert tips and tricks

Use room temperature ingredients

Especially for the plant milk, make sure that all ingredients are at room temperature. If your soy milk is cold, it makes it hard to mix it with melted chocolate and butter. Take everything out of the fridge beforehand and let them sit at room temperature before you start making this cake.

Don’t use extremely hot melted chocolate for buttercream frosting

One thing to be careful when making the chocolate buttercream frosting is the temperature of the melted chocolate. Do not use extremely hot melted chocolate as it can degrade the texture of the buttercream. Melt the vegan chocolate in bain marie and take it out of hot water halfway through and melt the rest of the chocolate chunks with the retained heat of the bain marie pot. This way the melted chocolate is not extremely hot.

Don’t take the cake out of the tin straight away

Cakes need time to set in the tin after removing from the oven, so rest the cake in the tin for at least 10-15 mins before transferring it to a cooling rack. Taking the cake out too soon also causes it to become dry as the cake is still very hot and the moisture evaporates from the cake quickly. Patience is key!

Recipe variations

• Try using my vegan caramel buttercream frosting to make brownie caramel cake!

How to store

• Refrigerating: The buttercream frosting is quite delicate so I recommend you store any leftover cake in the fridge. You can store the cake on a cake plate with a lid or put slices in an airtight container and store it in the fridge for up to 2-3 days. 

• Freezing: The cake can also be stored in the freezer. To freeze, place slices in a freezer-friendly airtight container or wrap them in a clingfilm and store them in the freezer for up to 2-3 months. Resting the cake in the fridge for a while in advance makes it easier to wrap the cake as it hardens the frosting.

*Although you can store this recipe in the fridge or freezer, it’s always best to consume it fresh and as soon as possible.

Want to master the basics of vegan baking?
Check out Vegan Baking 101 – the beginner’s guide to vegan baking for you to become an excellent vegan baker and familiar with the basics of vegan baking, ingredients, and techniques with useful tips!

You will LOVE this easy brownie cake because it is:

• easy to make
• so fudgy and decadent
• perfect for special events
• delicious

Want more recipes like this?

Try my other delicious dessert and cake recipes you might enjoy!

• Coconut cake
• No-bake chocolate mousse cake
• Ginger cake
• Plum cake
• Matcha cake
• No-bake chocolate tart
• Oreo cake
• Caramel cake

Visit the cakes and cupcakes page and recipe page for more delicious recipes!

Please leave a comment and rate this recipe with 5 stars in the comment section below if you like the recipe! Let me know and tag me @thechestnutbakery on Instagram too. Thank you for making my recipe, friends!

Recipe Card

Print