Preheat oven at 350 degrees F (180 degrees C).
Line 10x10 inch baking tray with parchment paper.
yolks and whites and set aside.
In a large bowl, mix egg yolks,
Vanilla Extract (1 tsp)
Caster Sugar (1/3 cup)
Corn Oil (1 oz)
Milk (1 oz)
together with a hand whisk, mix well and add in
Cake Flour (1/2 cup)
, mix well again. Divide egg yolk batter into two portions and blend the
Valrhona® Cocoa Powder (1 Tbsp)
Water (1 Tbsp)
mixture into one of the egg yolk batters.
For the meringue, whisk the egg whites until to foamy and add
Caster Sugar (1/4 cup)
in 3-4 batches. Continue to whisk egg whites until glossy and peaks form.
Gently fold half of the meringue to the egg yolk batter and cocoa batter with a rubber spatula.
Pour the plain batter on lined pan. Then gently pour cocoa batter on top of the plain batter and spread evenly with a spatula.
Draw lines closely for the entire pan top and down to and from with a ladle handle or use your index finger, then repeat the lines vertically.
Bake in preheated oven 350 degrees F (180 degrees C) for about 15 to 17 minutes.
Remove baking baking paper immediately after baked and leave cake to cool on wire rack with a clean parchment paper below, chocolate side at the bottom.
Trim off the sides of the cake and spread filling, then roll up the cake and chill in the refrigerator for a few hours before slicing.