Japanese Roll Cake

1. Oil the flat tray and cover the bottom of it with baking paper. Turn the oven on at 175 degree C. 2. Prepare ingredients A in separate container: 5 egg yolks, 50 gr sugar, 80 gr flour, 40 ml vegetable oil, 60 ml water 3. Prepare ingredients B in one bowl: 5 egg white, 40 gr sugar, 1/2 ts salt, vanilla, 15 gr corn flour. 4. Mix in high speed mixer the egg yolks and sugar until it is fluffy and then add the rest of ingredients A. Set aside. 5. Mix in high speed mixer all ingredients B until it is fluffy and then take a small bowl of it, add food coloring (Let's call this batter C). This small portion of batter B is used to decorate the outer part of the roll cake. 6. Make any patterns on the bottom of the tray using batter C. 7. Mix batter A and B well and pour...