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Trifle Bubble Cake

It's a bubble! It's a cake! It's a chocolate bubble filled with chocolate cake, raspberry jam, and pastry cream!


  • Pastry cream
  • 250ml of skim milk
  • 3 egg yolks
  • 50g sugar
  • 1tbsp flour
  • 1tbsp corn starch
  • 185g butter
  • 1 tsp vanilla extract
  • sea salt
  • Chocolate cake
  • 50g cocoa powder
  • 175g all-purpose flour
  • ½ tsp salt
  • ½ tsp bicarbonate of soda
  • 225g caster sugar
  • 175g unsalted butter, softened
  • 2 large eggs, at room temperature
  • 175ml milk
  • 800g dark chocolate (melted)
  • 200 pink choc melts (melted)
  • 8 tbsp raspberry jam


  1. Cake
  2. Preheat a fan-forced oven to 160C (320F) or 180C (356F) for a conventional oven. Line a 30 x 20cm baking tray with baking paper. Set aside.
  3. In the bowl of a stand mixer fitted with the paddle attachment, add the cocoa powder, plain flour, salt, bicarb soda and sugar. Turn mixer on low speed and allow it to mix for a couple minutes to help everything combine well! (alternatively you may do this by sifting the ingredients together). Add the softened butter there is no butter visible and it’s well incorporated into the dry.
  4. Next, add milk and eggs in a jug and whisk until well combined.
  5. Add wet ingredients to dry ingredients in a slow and steady stream until no dry ingredients are visible. Scrape down the bowl and mix for another 20 seconds.
  6. Pour batter into baking tray. Use a small off set spatula to spread around. Bake for 40 min.
  7. Once cooled use a 10cm round cookie cutter to cut out pieces of cake. Set aside.
  8. Pastry cream
  9. In a large mixing bowl, mix the yolks, vanilla extract (I added 3 tsp cos I think the vanilla really makes this custard amazing) and the sugar and whisk until well combined and the mixture lightens in colour. Add the corn flour and plain flour and stir until mixture is smooth Add 1/3 of the hot milk and stir well. Then slowly add the rest of the milk while stirring.
  10. Microwave for 1 minute at a time, stirring each time until mixture thickens and becomes smooth. You should be able to run your finger along the back of a spoon and it will be thick enough to not come back together.
  11. Add the cold butter cubes and stir until well combined.
  12. Transfer custard to a bowl, cover with plastic wrap and refrigerate for at least 3-4 hours or overnight to allow it to completely set.
  13. Chocolate Spheres
  14. To create spheres you’ll need a sphere mold. I bought mine on Amazon. If you search for Martellato Polycarbonate Chocolate Mold Half-Sphere 100mm, 2 Cavities it will come up in the results :0)
  15. Start off by adding melted pink choc melts to a piping bag. Drizzle it in the mold as demonstrated. Freeze for 10 minutes. Then pour dark chocolate in each mold to about half way. Use the back of a teaspoon to spread the chocolate to the top of the mold. Then turn over the molds onto a piece of baking paper or baking tray to allow excess to drip out. Freeze for 20 minutes. The chocolate spheres should slip around pretty easy once chilled because the warm chocolate contracts when put in the freezer and doesn’t stick to the mold.
  16. To finish molds off add a little bit of pastry cream at the bottom of each mold. Add the first layer of chocolate cake. Add some raspberry jam, followed by some more pastry cream. On only one half of the sphere add another layer of chocolate cake.
  17. To finish spheres add melted chocolate around the rim of one of the spheres and add the other half of the sphere on top of the melted chocolate joining the two halves to make one sphere. Wipe away any excess with a clean finger and allow to set before serving,
  18. To serve these spheres use a hot knife to careful cut in half. Each sphere serves 2 people.