unsalted butter, softened to room temperature • granulated sugar • eggs, room temperature and separated • vegetable or sunflower oil • vanilla extract • distilled white vinegar • liquid or gel red food coloring • all-purpose flour and 1 cup (130g) of cornstarch • unsweetened natural cocoa powder • baking soda • salt • vinegar and 1 cup milk (let it rest for 5 minutes) •