A towering and decadent chocolate explosion cake layered with white chocolate buttercream that comes with chocolate balls filled with sprinkles, glitter and sweets so the birthday girl or boy can smash them all over their cake. Piñata-style !

As a kid, I always had a piñata at every birthday party. My dad had been to Mexico and fell in love with the tradition, so each year we would make a piñata out of newspaper and glue, stuff it with sweets and toys and then, blindfold on, my friends and I would take turns to whack it until it eventually exploded and rained exciting goodies all over the place. This memory was the inspiration behind the most spectacular birthday cake of all – chocolate balls filled with sprinkles and glitter that the birthday girl or boy can smash all over their own cake!

This towering, colourful explosion cake is made up of my favourite chocolate cake, sandwiched together with vibrantly tinted white chocolate buttercream. The chocolate balls can be filled with whatever sprinkles, sweets or surprises you like – whatever you fill them with they are going to be LOADS of fun!  It’s one of the more advanced recipes in the book, but I know that many of you have been baking recipes from The Kate Tin for quite a few years now, and since you’ve had so much practice and really are incredibly good bakers now, I need to keep up with your skills and so I think this one is a nice challenge! I also don’t think I’m alone here when I say that, I don’t mind the effort if I’m baking for someone special! 

This fun creation comes straight out of my cookbook, ‘Chocolate’ which is a collection of 90 brand new recipes that champion my favourite ingredient, chocolate, in some rather unique ways! I’ve shared a few recipes from the book here and here. If you haven’t already got a copy, you can order it online from Loot or Takealot or find it in any bookstore nationwide! 

The reason for sharing the recipe for this celebratory chocolate explosion cake today is that it was exactly 9 years ago back in 2010 that I started The Kate Tin and published my very first post. I cannot quite believe that it has morphed into a brand, a couple of awards and a cookbook in just under a decade! If you’re a regular around here (which I know many of you are), I want to THANK YOU from the bottom of my heart, for clicking, liking, sharing and making my recipes and allowing me to inspire you with wickedly delicious bakes. Here’s to another 9 years!  

Chocolate Explosion Cake
Serves 8
Recipe extract from 'Chocolate' by Katelyn Williams published by Human & Rousseau
Total Time
4 hr
Total Time
4 hr
  2. 450 g (560 ml) white sugar
  3. 270 g (450 ml) cake flour
  4. 80 g (35 ml) cocoa powder
  5. 15 ml (1 tbsp) baking powder
  6. 15 ml (1 tbsp) bicarbonate of soda
  7. 5 ml (1 tsp) salt
  8. 2 large eggs, at room temperature
  9. 250 ml (1 cup) buttermilk
  10. 15 ml (1 tbsp) vanilla extract or essence
  11. 250 ml (1 cup) strong, hot coffee
  12. 70 g (70 ml) smooth peanut butter
  13. 110 g (110 ml) salted butter, melted
  15. egg whites from 3 eggs, at room temperature
  16. 225 g (280 ml) white sugar
  17. 125 g good-quality white chocolate, finely chopped
  18. 10 ml (2 tsp) vegetable or canola oil
  19. 400 g (400 ml) unsalted butter, cubed and softened
  20. at room temperature (don't use salted butter!)
  21. pink, blue, yellow, purple, green food colouring
  23. 400 g good-quality baking milk or dark chocolate,
  24. melted and cooled
  25. 8-hole silicone dome mould (see TIP)
  26. 200 g good-quality baking white chocolate, melted
  27. sprinkles, popping candy, edible glitter, to fill
  28. pink, green, yellow, blue powder food colouring
  1. Preheat the oven to 180 °C (160 °C for fan-forced). Prepare 3 springform cake tins (18 cm each).
  2. For the cake, mix all the dry ingredients together. Whisk the eggs, buttermilk and vanilla and add to the dry ingredients. Combine the coffee, peanut butter and butter and add to the mixture. Mix well.
  3. Pour 300 g of the mixture into the prepared cake tins and bake for 15–20 minutes or until a skewer
  4. comes out clean. Allow to cool for 10 minutes before inverting and allowing to cool completely. Clean and prepare the cake tins again and bake the remaining batter to make the last two layers.
  5. To make the buttercream, fill the bottom of a saucepan with water and bring it to a gentle simmer.
  6. Place the egg whites and sugar in a bowl that fits over the saucepan and place the bowl over the hot water, stirring gently with a whisk (don’t whisk to aerate the mixture). Keep stirring until the mixture reaches 60 °C on a sugar thermometer or until the egg whites are hot to the touch. Transfer the hot mixture to the bowl of a stand mixer and, using the whisk attachment, whip the mixture on high until light and fluffy. Continue whipping for a good 10 minutes or until the meringue is cool to the touch. In the meantime, melt the white chocolate and oil together until smooth and set aside to cool. Slowly add the butter, one block at a time, to the meringue until it is thick, glossy and velvety. Check the temperature of the melted white chocolate – it should be cool to the touch – then whip it into the buttercream. Divide the buttercream into five batches and tint each using the gel food colouring. Place each colour into a piping bag and snip off the tip.
  7. To assemble the cake, place one layer on a cake stand or serving plate, then pipe dots of green icing to cover the cake. Top with the second cake layer, and pipe dots of another colour of icing on top. Repeat the process, finishing with a layer of icing dots.
  8. To make the chocolate domes, fill the silicone dome mould with the melted and cooled dark or
  9. milk chocolate (it shouldn’t be hot or it will melt the splatters), then flip the mould over the bowl of melted chocolate and allow the excess chocolate to drip out.
  10. Allow to set in the fridge and repeat the process to form a nice thick shell.
  11. Once set, pop the domes out of the mould. Fill one dome with a mixture of sprinkles, popping candy and edible glitter. Dip the edges of another dome in a little melted chocolate (you could also use a hot baking tray), then ‘glue’ the empty dome on top of the one filled with sprinkles to form a ball. Seal the edges and allow to set. Repeat with the remaining balls.
  12. Divide the white chocolate into four small bowls and tint each a different colour. Splatter and splash the various coloured chocolates onto the domes and allow to set. Arrange the chocolate balls on top of the cake and top with sparklers. To serve, smash the balls with the back of a spoon to release the sprinkles inside!
  1. TIP: You could also bake this cake in three tins and then cut each cake in half to make six layers.
  2. The remaining layer you can wrap and freeze for cake emergencies!
  3. Silicone dome moulds are available at baking or plasticware shops but if you can’t find them, you
  4. can also use 6 to 8 small water balloons that have been washed well. Simply dip the balloons in the chocolate first, and then splatter with the coloured white chocolate.
The Kate Tin https://thekatetin.com/




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