NZ Woman's Weekly

Chocolate rainbow cake recipe

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  • Occasion

    Special occasion

Hosting a children’s party at home can be really special – all you need is a few handy recipes like this chocolate rainbow cake.

The trick is to get the icing colours just right (try gel colours from cake shops). Finish with marshmallows and chocolate coins.

Serves 20

  • 4 cups flour
  • 2 tsp baking powder
  • 4 tsp baking soda
  • 1 cup cocoa
  • 1 tsp salt
  • 3 cups sugar
  • 4 eggs
  • 2 cups milk, plus
  • 2 tbsp cider vinegar
  • 2 tsp vanilla essence
  • 1 cup canola oil
  • 1 cup hot water
  1. Preheat oven to 180°C. Fully line a 24 x 30cm high-sided cake tin with baking paper. Sift flour, baking powder, baking soda, cocoa and salt into the bowl of an electric mixer and stir in sugar.
  2. Whisk together eggs, milk mixture, vanilla and oil, then pour into mixer bowl along with hot water. Beat on medium for 1-2 minutes until well combined.
  3. Pour into tin and bake for about 1 hour 20 minutes (test with a skewer). If it is getting too brown on top, cover loosely with tin foil. Leave to cool in tin.


  • 500g butter, softened
  • 12 cups (1.5kg) icing sugar, sifted
  • 2 tsp vanilla essence
  • ½ cup milk
  • Gel food colours
  • 6 piping bags and petal-tip nozzle
  1. Cream butter for 2-3 minutes until very pale. With beaters on a low speed, add icing sugar and vanilla, alternating with milk – aim for a creamy but firm icing.
  2. Put cake on a large board and use a serrated knife to shape into a rainbow (use a large pan lid as a guide for the outer edge, a small bowl for the inner).
  3. Cover top and sides with a thin layer of buttercream, then refrigerate for 15 minutes. Add a second smooth coat and refrigerate for 15 minutes.
  4. Divide remaining buttercream into six bowls and tint red, orange, yellow, green, blue and violet. Cover with plastic wrap.
  5. Fill a piping bag with red icing and pipe two rows of ruffles from one end of rainbow to the other. Repeat with other colours, refrigerating cake in between colours to keep it firm. Pipe inside edge with violet.

About Jo Wilcox

"I have had a love of food my whole life. Lucky for me my mum allowed me to play in the kitchen from the very beginning – from sitting up on the bench watch her peeling peaches for preserving or planning dinner parties from her many Womans Weekly Cookbooks. Starting in my local beach café, I went onto professional cookery training and my big foodie OE working as a professional chef and nanny. At 21 I launched my first restaurant. The following years saw me owning a gourmet cake and dessert shop and then a pasta deli before I discovered the world of food styling. Today I work in food styling making food look beautiful and tasty in packaging and advertising shoots, as well as my most important role yet – Food Editor of New Zealand Woman’s Weekly. I aim to provide great meal solutions that are interesting and approachable, and of course gorgeous foodie photos that make you want to cook them! I love the feedback and the knowledge that people actually cook them and have great results. If I can give someone a love of cooking and enjoying family meal times and gatherings then my job is done!" See

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Issue 1541

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