How to Prepare
Preheat & Line Pan:
Preheat oven to 350F 177C.
Line a 12×18-inch sheet pan with parchment paper.
Prepare the Cake Batter:
Separate egg yolks and whites.
Beat egg yolks with 1/2 cup sugar until pale yellow and thick.
Add vegetable oil, milk, and vanilla extract; mix well.
Sift cake flour, cocoa powder, baking powder, baking soda, and salt; add in thirds to the egg yolk mixture.
