Rainbow Hurricane Cake Roll

After some hiccups, I'm getting it right for this rainbow hurricane cake roll! Though there's lots of air pockets in the cake roll, it still pretty to look at! After baking so much swiss roll, think I'm finally overcome my fear of the rolling up process. ^0^

Ingredient (10"x10" pan)

Rainbow Batter

• 3 egg yolks
• 1 tsp vanilla paste
• 40gm rice bran oil
• 45gm fresh milk
• 55gm cake flour
• wilton food colourings 

Blue Batter* (for cocoa layer, omit blue colouring, use cake flour 15gm, cocoa powder 10gm)

• 1 egg yolk
• 1/2 tsp vanilla paste
• 15gm rice bran oil
• 20gm fresh milk
• 25gm cake flour
• wilton food colouring

Meringue

• 4 egg whites
• 60gm fine sugar
• 1/4 tsp cream of tartar

Method

1. Whisk egg yolk with vanilla, oil and milk till well combined. Sift in cake flour and mix till a smooth batter is formed. Divide batter into 3 equal portions. Add in drops of food colourings and mix well. 
2. Repeat steps for blue batter.
3. In a clean dry bowl, beat egg whites and cream of tartar till foamy. Add in sugar and beat till firm peaked formed. Divide meringue into 4 equal portions, approx 50gm each. Fold each portion into individual tinted egg batter.
4. Spread the rainbow batter (pink, yellow, green) separately onto lined cake pan. Gently spread the blue batter on top of the rainbow batter. Using your index finger, draw vertical lines from top to bottom from one side of the pan to the other side. Repeat drawing horizontal line from left to right. Tap the pan lightly on work top to remove excess air bubbles.
5. Bake in preheated oven at 180 deg cel for 20-25 mins. Cool in pan for 5 mins. Flip the cake onto a clean paper. Remove the base lining. Gently roll up like a swiss roll. Leave to cool completely before frosting. Frost and chill for at least one hour before slicing.