Preheat oven to 350 degrees. Grease a sheet pan or jelly roll pan that is something close to 15 ½” by 11 ½”. Line with parchment paper and grease that too.

Beat egg whites until glossy and soft peaks form. In a separate bowl beat the egg yolks with the granulated sugar until thick and pale yellow in color. Stir in cocoa powder and granulated espresso/instant coffee. Take a big scoop of the egg whites and mix into the yolks, then fold the yolks into the egg whites. Pour into prepared pan and even out with a spatula.

Bake in pre-heated oven for 20 minutes. Remove pan from oven and let cake cool in the pan. When cool, tip the cake onto another piece of parchment paper that has been dusted with powdered sugar.

For filling, mix mascarpone cheese with cream until well mixed and creamy. Smooth the filling over the cooled cake.

Using the parchment paper to help you, roll the roulade up from one of the short ends. Carefully lift it and place on a serving platter. It may crack but that is fine. Dust with additional powdered sugar and grate some chocolate on top if desired. Chill in fridge for at least half an hour but serve the same day as you make it. Slice to serve.