overhead shot of square chocolate cake on a wire rack

Dark Chocolate Traybake

Irresistible extra dark chocolate traybake topped with silky-smooth and and creamy chocolate buttercream

Course Dessert
Cuisine American
Keyword chocolate cake, snack cake, traybake
Prep Time 20 minutes
Cook Time 30 minutes
Servings 8 people


  • 100 g dark chocolate ( min 70% cocoa solids) chopped
  • 250 ml hot, freshly brewed, strong coffee
  • 120 ml Greek yogurt
  • 120 ml olive oil
  • 120 ml milk
  • 2 large eggs plus one egg yolk
  • 1 1/2 tsp vanilla
  • 270 g all purpose flour
  • 365 g caster sugar
  • 75 g Dutch processed cocoa (I used Green & Black organic cocoa powder)
  • 2 tsp baking soda
  • 1 tsp baking powder
  • 1 tsp salt

For the buttercream:

  • 200 g dark chocolate (min 70% cocoa solids) chopped
  • 340 g unsalted butter softened
  • 1 tsp vanilla
  • 1/4 tsp salt
  • 270 g icing sugar


  1. Pre heat the oven to 175 C ( 160 C fan). Lightly grease two 8- inch square cake tins and line them up with baking parchment.

  2. Place 100 g chopped dark chocolate in a heatproof bowl and pour the hot, freshly brewed coffee over it. Cover the bowl with clingfilm and set aside.

  3. In a medium bowl, combine together yogurt, olive oil, milk, eggs and vanilla. Whisk to combine and set aside.

  4. In a bowl of a standing mixer, fitted with paddle attachment, mix together flour, sugar, cocoa, baking soda, baking powder and salt on a low speed until combined.

  5. With the mixer still running on the low speed, slowly add the yogurt mixture. Mix on medium speed for 30 seconds, until well combined.

  6. Stir the chocolate and coffee mixture until smooth. Slowly pour this mixture into the rest of the batter, mix on low speed until incorporated.

  7. Remove the bowl from the mixer and scrape down the sides with spatula, ensuring that everything is well combined, but don't over mix it. Pour the batter into prepared cake tins and spread it evenly in the tin.

  8. Bake for 25-30 minutes or until toothpick inserted in the middle comes out clean. It's OK if there is a bit of crumb remaining.

  9. Remove from the oven, allow the cakes to cool for about 10 minutes, then transfer the cakes into a cooling rack and allow them to cool completely before frosting it.

To make buttercream:

  1. Melt the dark chocolate in a heatproof bowl set over a pan of simmering water, stirring it constantly. Once melted, remove from the heat and cool slightly.

  2. In a bowl of a standing mixer, fitted with the paddle attachment, cream the butter on a medium high speed for 3 minutes, until pale and fluffy.

  3. Add the vanilla and salt and beat on medium speed until incorporated. Reduce the speed to low, and carefully add the icing sugar.

  4. Once combined, increase the speed to medium high and beat until smooth and silky, about 3 minutes. Make sure to scrape the sides of the bowl from time to time. Add melted chocolate to the sugar and butter mixture, mix on low speed until fully combined.

  5. Frost the cooled cake with the buttercream and enjoy!

Recipe Notes

Store any leftover cake in the airtight container for up to 3 days.

This cake can also be made in advance and frozen. Make sure to wrap it tightly with clingfilm (once it has fully cooled) and store in the freezer. Take it out of the freezer and defrost fully when ready to eat.