Watermelon Mousse Cake

I came across this video by Mosogourmet on Youtube last weekend and really liked this watermelon mousse cake. This is my 2nd attempt at this cake as the mousse didn’t set well during my first attempt.

The cake mould used is a semi-circular log shaped roll mould, I was quite lucky I managed to find one at the local baking shop.

watermelon mousse cake using matcha swiss roll | Bento Days

watermelon mousse cake | Bento Days


The video description actually lists down the ingredients and recipe. I used that combined with other sources online listed below to get a better idea of how to make this cake.


Matcha Swiss Roll (recipe adapted from here)

  • 4 eggs, separated into 1 egg white, 3 egg whites, and 3 egg yolks.
  • 2tsp matcha powder (dissolved in 60ml of hot water)
  • 65g castor sugar
  • 40ml salad oil
  • 1 tsp Vanilla extract
  • 80g cake flour

2tsp matcha powder for painting of watermelon stripes

Watermelon mousse (recipe from here)

  • 1.5 cups  watermelon puree
  • 1 tbsp powdered gelatine
  • 1/4 cup sugar
  • 2tsp lemon juice
  • 1/2 cup cold whipping cream
  • 1/2 cup mini chocolate chips

– Line baking pan with parchment paper
– Whisk egg yolks and half the castor sugar till thick and pale.
– Add water, salad oil and vanilla extract, and mix well. Sift cake flour into mixture and whisk till ribbon stage
– In a clean mixer bowl, beat ONE egg white till you achieve stiff peaks
– In a separate bowl, add 2tsp matcha powder to 4tsp of green tea egg yolk mixture. Add 3tbsp of egg white meringue to the above and mix well. Place mixture into piping bag and pipe stripes onto the middle portion of parchment paper
– Bake for 2 mins in preheated oven of 170 degrees C. Remove from oven and set aside
– Meantime, beat 3 egg whites til frothy and add in the remaining egg white meringue from the earlier process. Continue beating till you achieve slightly stiff peak. Add in the remaining 30g castor sugar. Beat till you achieve a shiny texture and add in the remaining corn starch and continue beating till stiff peak
– Fold in meringue in 3 additions to egg yolk mixture
– Spread the cake mixture onto baking tray and bake for 15 mins (do not overbake!).

-Remove tray from oven, and flip the cake over carefully onto a clean baking paper (so that the designs are facing the top). Remove the parchment paper from the design very carefully.

-While the cake is still warm, cut it to the length of the cake mould. Place cake with design faced down on a piece of parchment paper and place cake (together with paper) into mould. It is important to work quickly while the cake is still warm so it does not crack during the process of putting into the mould.

– Meanwhile make the watermelon mousse. Add the gelatin to a quarter cup of watermelon mousse and let it stand to soften.

– Heat the rest of the watermelon puree in a saucepan with the sugar and lemon juice over low heat and stir until sugar is dissolved. Add the gelatin mixture and stir to combine. Let it cool to room temperature.

– Whisk the whipping cream until soft peaks form. Do not overwhip or the cream will separate. Stir the cream into the cooled watermelon puree mixture, until there are no lumps. Stir in some chocolate chips for the “watermelon seeds”.

– Pour into the cake mould and let it set overnight.

It sounds like quite a bit of work but trust me, the cake is super yummy and totally worth the effort!


5 thoughts on “Watermelon Mousse Cake

  1. This is such an unique recipe Jean. Well done!!! Can you share where is that shop to get this semi circular tray? I am thinking if it can help with baking a baguette. 🙂 Warmly, danny

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