- Preheat oven to 180°C.
- Place egg yolks and sugar in a mixing bowl and beat for 10 mins on high speed. Meanwhile, whisk butter until light and fluffy. Set aside. Once the eggs are ready, turn the speed down and sift in flour and milk powder. Add vanilla extract and orange zest. Then, fold in butter. Divide the mixture into 3 equal portions. Mix in cocoa powder into one of the mixture portions. Stir to mix well.
- Pour each mixture portions into 3 different trays lined with baking paper. You can use an 8” or 6” round trays, 8” or 6” square trays or 7.9” x 4.3” loaf pans. Bake them at 180°C for 35 mins.
- Once ready, leave to cool. Then, spread a layer of blueberry jam over the top of the cocoa cake and a layer over one of the orange cakes. Setting the orange cake with blueberry jam as your base, place the cocoa cake on top and finally, stack on the orange cake that’s without any jam.
- Trim the edges and serve.