Easy Rainbow Roll Cake

Описание: A light spongy roulade cake filled with vanilla whipped cream, brought to you ... by the letter T. haha ...lame.
This is a really quick cake you can make in advance, put together in 30-40 mins, and have it ready for dessert.

My first cooking how-to using Sony RX100 MK1.
Yes, I know I need something better with an external mic, and work on angles.

Ingredients:
4 whites
60g caster sugar
1 tsp cream of tartar
4 egg yolks
20g caster sugar
40ml milk
40g vegetable oil
30g cake (low gluten/soft) flour
30g corn flour
Natural food dyes.

Method:
Whip the whites until foamy.
Add the sugar in 3 parts, then add the cream of tartar.
Meringue should take about 6 mins total until stiff peaks.
Beat the yolks with sugar until light and foamy.
Add the oil and milk and continue to beat until emulsified.
Add the yolks to the meringue and whip together.
Sift in the cake flour and corn flour.
Fold gently until fully incorporated.
Divide the mixture into even parts and add the food dye.
Gently fold through until the colour is uniform.
Pour into disposable piping bags.
Pipe the mixture into a lined baking pan, alternating colours.
Drop the pan from a low height 2-3 times to get rid of trapped air.
Bake in a pre-heated oven at 165 Celsius for 14 minutes.
Fill the sponge cake with whipped cream (fruit optional) and gently roll the cake up.
The cake shouldn't be too cool before this, otherwise it will crack when rolling.
Refrigerate for at least an hour for the cream and cake to set together.
Alternatively, leave out the dye and sift in 1tbsp cocoa or green tea, for a different flavoured sponge.
Enjoy!