Preheat your oven to 400°F (200°C). Line a jelly roll pan with parchment paper and lightly spray with baking spray.

In a medium bowl, sift together the plain flour and instant espresso powder.

Using an electric mixer, beat the egg whites until foamy, gradually add sugar, and continue whipping until medium peaks form.

In another bowl, combine the egg yolks, whole eggs, and a portion of sugar, and whip until it reaches the ribbon stage.

Gently fold the beaten egg whites into the yolk mixture in three additions.

Slowly add the sifted flour and espresso powder mixture to the cake batter and fold until no dry flour remains.

Spread the batter evenly in the prepared pan and bake for 8 to 10 minutes or until lightly golden.

Once baked, roll the cake in the parchment paper tightly and allow it to cool for 20 minutes.

In a mixing bowl, combine the heavy cream, powdered sugar, vanilla extract, and coffee liqueur, then beat until soft peaks form. Fold in mascarpone cheese.

Spread half of the cream filling over the cooled cake, roll it tightly back into a log, and frost the outside with remaining filling.

Dust with cocoa powder before serving and trim the ends of the log for a clean presentation.