For egg whites into the bowl very clean (no water, no oil), divide the sugar into 3 times, just for just hitting.

Until you see the stiff cotton mixture.

Put the egg white mixture in the refrigerator to keep cold for a while.

Add egg yolk, water, soy oil, beat well, then sift in flour, continue to mix.

Remove the egg white from the fridge, divide it into two parts, and mix.

Divide the mixture into 4 equal parts, each part you add 1-2 drops of food coloring, mix well.

Pre-lay the parchment paper around the baking pan, adding each color mixture one after another, each color you can pour into a different corner of the mold, or you pour out in a range of colors.
Preheat the oven to a temperature of 180 degrees C, put the bread into the baking for 10-12 minutes, until you use a toothpick to skewered and pulled out the toothpick does not stick.
Wait for the cake to cool down, remove the whipped cream, spread it on the cake and roll it up. Before you use you to cut the cake into many slices to taste, sip with some hot tea is best.