In a mixing bowl of a stand-in mixer beat whipping cream with egg whites and 4 tablespoons of sugar on medium speed until stiff peaks form. Scrape out this mixture in a bowl and set aside. This is filling #1(Note: Make sure the mixture is not runny! and the whipped cream is light, airy, and holds it shape)
Add egg yolks and sugar to the mixing bowl. Beat the egg yolks with 4 tablespoons of sugar on medium speed till you get a creamy light yellow mixture. Add mascarpone cheese and continue to mix till it is well blended. This is filling #2.
Dip the ladyfingers in the coffee and lay them in a 7 by 11 Pyrex tray one by one till the bottom is completely covered. (Note: Dip one ladyfinger at a time - do not soak them).
Spread filling #2 (egg yolk - mascarpone cheese mixture) over the ladyfingers gently using a spatula till the ladyfingers are evenly covered. Follow it by a layer of coffee-dipped ladyfingers.
Spread filling #1 (egg white and whipped cream mixture) over the ladyfingers gently and evenly using a spatula.
Sprinkle cocoa powder over the cake evenly and garnish with shaved chocolate.
Cover the tray and refrigerate the Tiramisu for 4-6 hours, until set.