Preheat an oven to 350 F. Spray a 10” x 15” jelly roll pan with nonstick cooking spray. Line the pan with parchment paper and spray the paper with nonstick spray.
Separate the eggs. Then whip the egg whites with ½ cup powdered sugar until stiff glossy peaks form.
Whip the egg yolks with the remaining powdered sugar and vanilla until light and fluffy, about 5-7 minutes.
Combine the flour to the kosher salt. Add the dry ingredients to the egg yolk mixture as well as the melted butter. Mix on medium speed until just combined.
Gently fold in the egg whites. Be careful not to under or overmix. You shouldn’t see any streaks of egg white, but you also want to be careful to fold gently until all is incorporated.
Pour the batter into the prepared pan. Spread the batter smooth with an offset spatula. Bake for 10-11 minutes or until the cake is springy to the touch, but do not overbake.
While the cake is baking, dust a thin kitchen towel with 2 tablespoons of cocoa powder in a 10” x 15” rectangular shape. Once the cake comes out of the oven, immediately invert it onto the cocoa-dusted towel. Remove the parchment paper and then roll the cake into a tight roll. Allow the cake to cool completely at room temperature. Doing so is what helps shape the cake.
Once the cake is cool, combine the ingredients for the vanilla whipped cream. Whip until stiff peaks form.
Unroll the cake and evenly spread with the whipped cream. Roll the cake back up into a tight roll. Place the cake onto a baking sheet that has been topped with a cooling rack. Refrigerate until firm, about 30 minutes to one hour.
Prepare the ganache by microwaving the cream for one minute until very hot. Add in the cocoa powder and whisk until smooth. Add in the powdered sugar and vanilla. Whisk again mixture again. Pour the warm ganache evenly over the chilled cake, then refrigerate for at least 30 minutes before slicing.
Tips
For successful stiff egg white peaks, make sure no egg yolk falls into the whites. The best way to do this is to separate the yolks from the whites into a separate bowl before combining all whites.
Make sure to pour the ganache over the finished cake while it is still warm. If making the ganache ahead of time, gently heat it in the microwave until slightly warm and pourable.
