1. Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius). Line a 12×17-inch (30×43-centimeter) baking sheet with Gefen Parchment Paper and spray well with cooking spray.
2. In the bowl of a mixer, beat egg whites with 1/3 cup sugar until stiff peaks form. Transfer egg whites to another bowl and set aside.
3. In the mixer bowl, beat egg yolks, remaining 1/3 cup sugar, and vanilla extract until pale and creamy. Add coffee and oil and sift in the flour, baking powder, and cocoa. Mix until well combined.
4. Using a rubber spatula, gently fold in egg whites. Make sure to fully incorporate whites with chocolate batter, but do not overmix. Spread batter evenly over the baking sheet and bake for 10 minutes.
5. While the cake bakes, lay a clean dishtowel on the counter and lightly dust it with cocoa powder.
6. When the cake is baked, remove it from the oven, run a knife around the edge of the pan to loosen the cake, and gently flip over onto the dishtowel. Tightly roll up the cake along the long side (along with the parchment paper) and set aside to cool.