Vegan Double Chocolate Cake with Vanilla Buttercream Icing

If you don't follow me on social media you may have missed my birthday last Friday and the abundance of vegan junk food I shared on Instagram. The star of the show was definitely my birthday cake, though, and today I'm here to share the recipe!

I baked myself a four layer chocolate cake complete with vanilla buttercream and a dark chocolate covering. The entire thing took me around four hours to bake and assemble and it even involved me taking a little trip to the local Co-Op on my own. Yep. It was a really big deal for me and it was even more rewarding because it was something I'd done completely by myself and for myself.
For the cake ::
♥ two boxes of the Betty Crocker Devil's Food Cake mix.
♥ 660ml (two cans) of Diet Coke.

For the buttercream icing ::
♥ 250g dairy-free butter. I used Flora.
♥ 500g icing sugar.
♥ 2 teaspoons vanilla extract.
♥ An amount of unsweetened almond milk.

For the chocolate coating:
♥ 250g dairy-free chocolate. I used Co-Op's own brand dark chocolate.
♥ Optional: vegan sprinkles.

1. Grease two 9 inch cake pans. Preheat your oven to 180oc.

2. Empty the contents of one box of the cake mix into a bowl. Slowly pour in one can of coke, distributing it evenly across the mix. Wait a few seconds for it to bubble and froth up.

3. Using a hand mixer (or a hand whisk) beat the coke and dry ingredients together for about one minute on a medium speed. Then turn the speed up to high and beat for another two minutes.

4. Your cake batter should be a rich chocolate colour and smooth like regular cake batter. Distribute it evenly between your two pans and bake for 20 minutes.

5. Repeat this process until you have four cakes! Leave them to cool completely before you begin to prepare the buttercream.
6. To make the vanilla buttercream, cream together the butter and vanilla extract for a minute or two. Add the icing sugar in stages and mix until it's fully combined. I found that my icing was waaay too thick at this point and loosened it up with at least 4 tablespoons of almond milk. You can do this by eye, though, and if you feel your icing is a good, spreadable consistency already then feel free to add less. On the other hand, if it's still too thick and firm then add a little more milk.

7. Now it's time to assemble the cakes! Place one of your cakes on a good, level surface like a cake board before you begin. It's also a good idea to use something you won't be presenting it on because the chocolate covering gets very messy later on!

8. Apply a generous amount of buttercream to the top of your cake and smooth it evenly over the entire surface. Once you're satisfied pop another cake on top, and do this until you've used all of the cakes. Don't apply any buttercream to the top cake though!

9. Pop your cake into the fridge to chill whilst you prepare the chocolate. To do this, simply melt your chocolate in a bowl. Yep, it's that simple.

10. You can now begin to smother your cake in melted chocolate! I started by pouring around 100g on top and guided it gently over the edge whilst keeping the top surface level. At this point you want to add your sprinkles so they weld in with the chocolate. I then coated the sides with a thin layer of chocolate and popped it into the fridge for a minute or so to harden before I coated it with another layer. Put it in the fridge to harden completely and then serve whenever you'd like. There's probably a more professional or efficient way to do this but I just kind of made it up as I went along!

Aaaand that's it! I found I struck the perfect icing-to-cake ratio with this recipe and I quite like the pure chocolate coating instead of more icing. Icing is my least favourite thing! If I'm eating a cake I want to eat cake, ya feel me. The chocolate did make cutting slices a major pain in the ass as it just cracked into shards but at least it looked nice. The cake itself was everything I could have dreamed of: chocolatey, fudgy and the perfect moist squishy texture. I wholeheartedly recommend the Diet Coke trick! I was really dubious about it but it turned out perfectly. Plus it meant I got to lick the bowl without risk of salmonella, hah.


  1. This looks absolutely incredible, Lauren!! Nothing beats some buttercream in my eyes, and even better than this entire thing is vegan! Hope you had the most wonderful birthday (:

  2. This looks amazing and I can't believe it was vegan! I hope you had the most wonderful birthday! :) xx

    Yasmina | The July Journal

  3. This looks so amazing Lauren! I've never tried making a vegan cake before but I'll definitely need to give this recipe a go, thank you so much for sharing it!

    Carolyn x
    Faithfully Carolyn

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  5. This looks incredible - I never knew coca cola was an alternative to use in the cake boxes. So great to know, I'm defiantly going to make one now!

  6. Omg I saw this on your social media and have been waiting for you to post the recipe! I can;t wait to make this, it looks so delicious I'm so excited!


  7. This looks absolutely delicious, definitely adding it to my list of recipes to try! I hope you had an amazing birthday, Lauren :) xx



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