How To Make A Chocolate Explosion Cake

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My son celebrated his 18th birthday recently and I made this chocolate cake for him. It went down a real treat and everyone loved it! I’m now going to show you how to make a chocolate explosion cake in this post!

I used to make celebration cakes and cupcakes a lot for friends and family, some of which I’ve shared on my blog. I stopped making cakes regularly a few years ago, so my cake making skills were at an all time low when I made this chocoholic’s dream cake. Good thing that this cake is so easy to put together… All you need is a chocolate cake, some chocolate frosting and a whole load of chocolate bars!

How to make a Chocolate Explosion Cake. It looks amazing (and yummy) and is so easy to make! This is a chocolate lover, chocoholics dream cake! Perfect for birthdays and other celebrations!

How to make a chocolate explosion cake

I’ve been seeing these kind of cakes all over Pinterest for a while now, and knew I wanted to have a go at making one too. Liam’s 18th was the perfect opportunity!

Now, the reason why I have described this as the easiest birthday cake ever is because I didn’t make a thing… it was a complete assembly job, thanks to store bought chocolate cakes, frosting, and chocolate bars. Don’t get me wrong, if you want to make your own cake and frosting, please do. If I had more time, I would have done the same, but I didn’t. I’ve included my go-to chocolate cake recipe at the end of this post.

Chocolate for Chocolate Explosion Cake

I had no plan going into this cake, I literally just bought a bunch of my son’s favourite chocolates and chocolate bars and hoped I would have enough! That said, I will give the approximate quantities I ended up using for a better guide than my ratchet way of making a cake!


  • 20cm/8″ chocolate cake – the height needs to be about 10cm/4″ – I stacked two Tesco large chocolate birthday cakes on top of one another, no need for support between the layers
  • 400g can Better Crocker Milk Chocolate Icing
  • 4 finger Kit Kats (10-12 packs)
  • 40 Maltesers (2-3 regular bags)
  • 40 Chocolate Buttons (3-4 treat size bags)
  • Kinder Egg x 2 (just in case one breaks, if they both do… oh well, hide it with M&Ms!)
  • M&Ms – your favourite kind, I used Crispy and Peanut (2-3 of each)
  • Reese’s Peanut Butter Cups (2 x 3 packs)
  • Kinder Bueno (2 bars)
  • Dairy Milk (2 bars)
  • Snickers (2 bars)
  • Flake (2 bars)
  • Milky Bar (2 bars)


  • cake stand or plate
  • spatula or knife
  • piping bag or plastic food bag
  • scissors
  • birthday age candle (optional)

How to make a chocolate explosion cake


If you are making your own cake, you will need to cover it completely with chocolate frosting. My store bought cakes were already frosted so I didn’t need to – but I did add a layer of frosting on the top to cover the writing that was on it 😝

  1. Place the cake in the middle of the cake stand.
  2. Break the KitKats into two finger pieces. I used 11 KitKats, plus one finger!
  3. Spread some frosting on the back of each KitKat and start to add around the cake. Make sure that all of the embossing is facing the same way, and that the bottoms are touching the cake stand.
    • I added the Maltesers and Buttons around the cake because it was a bit higher than the KitKats and I wanted to hide it. So, if you’re going to do the same, you will need to stick them on with some frosting. If you don’t have a piping bag, use a plastic food bag instead – just add a big spoonful of frosting, and squeeze it down into one corner. Snip off the tip and away you go!
  4. Squeeze a blob of icing onto each of the Maltesers, and stick to the cake on top of the KitKats.
  5. Squeeze a blog of icing just behind and between each of the Maltesers and gently press in the Buttons.
    • Use photo above for reference!
  6. Now it’s time for the fun part – making the chocolate bar explosion!

Chocolate Explosion Cake

  1. I found it easier to work from a focal point. In my case it was the 18 candle that I placed about a third of the way up the cake in the center. If you’re not using a big candle like this, another focal point could be a shaped piece of chocolate like a chocolate bear or chocolate egg.
  2. I started towards the back of the cake, gently poking the chocolate bars into the cake, deep enough so that they would stay standing. For added support, I added blobs of frosting with the piping bag. Some bars I broke up into pieces, and the Snickers bar I cut in half on the diagonal. Basically, just add chocolate bars until you are happy with the way it looks!
  3. I then split open the Kinder Eggs – open shattered completely, the other one was a lot better, and I hid the broken bottom bit with some M&Ms, and added some more to sit inside the egg havlves. I tucked in the Reese’s Peanut Butter Cups, and halved one to make it look like it was stuck inside the cake. I then filled in the front of the cake with loads of M&Ms.
  4. And that is IT. Literally stick chocolate bars into a chocolate cake – ta-dahhhh!

Chocolate Explosion Cake

Chocolate Cake
Author: Michelle Ordever
Prep time: 20 mins
Cook time: 60 mins
Total time: 1 hour 20 mins
  • 100g unsalted butter, melted
  • 250g caster sugar
  • 50ml sunflower oil
  • 25g cocoa powder
  • 2tsp vanilla extract
  • 4 medium eggs
  • 80ml milk
  • 100ml double cream
  • 300g plain flour
  • 3tsp baking powder
  1. Pre-heat oven 180C/350F/Gas 4
  2. Grease and line an 8″ cake tin
  3. Place the melted butter, caster sugar, sunflower oil, cocoa powder, and vanilla extract into a mixing bowl, and beat well.
  4. Beat in the eggs, until well combined, then beat in the milk and cream, until the mixture is smooth.
  5. Sift the flour and baking powder into the chocolatey batter, and fold in. You will find that the mixture is a bit runny, but this is how it should be!
  6. Pour the mixture into the prepared cake tin and cover with foil.
  7. Bake for 35 minutes covered, and for 25 minutes uncovered.
  8. When cooked, the cake should be springy to the touch, and a skewer come out clean when inserted in the middle.
  9. Leave to cool completely in the tin before turning out.
  10. Decorate as desired.

You might also like to try my Chocolate Cherry Cream Cake recipe.

Chocolate Bar Cake

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