Make the ladyfingers:

Beat the egg whites until foamy. Gradually add the sugar beating well after each addition. Continue to beat at medium speed to incorporate more air. Beat until very thick but not dry or cracking.

Add the egg yolks folding very gently with a rubber spatula.

Sift the flour, cornstarch and cocoa over the egg mixture. Fold gently just until blended.

Gently fill a pastry bag that has a 3/4" tip or hole cut into the point. Pipe  2 1/2" lengths of batter about 3/4" apart.

Bake at 350' until lightly browned, about 7 minutes or so (may just look darker because of the cocoa). Ladyfingers will be firm to the touch but shouldn't be hard or brittle. If they are spongy, they will collapse...better more firm than too soft. Remove from oven and set aside to cool.

Make the filling:

Combine egg yolks and sugar in a mixing bowl set over a pot of simmering water. Stir and heat to 140' to cook the egg yolks. Don't overheat as this may result in cooking the eggs....I was borderline on this as I was distracted. Keep the focus at this stage. When hot enough, remove from the heat.

Put the mixing bowl onto the stand and beat until very thick, pale yellow and cool, about 10 minutes.

When the mixture is cool and lemon color, add the mascarpone cheese and mix just until blended. Transfer mixture to a large bowl and set aside. Wash bowl well.

Pour the heavy whipping cream into the clean bowl. Whip until very thick. We don't want butter but we want a stable whip cream.

Fold the whipped cream into the mascarpone mixture.

Blend just until smooth.

Place an 8" or 9" ring from a springform pan onto a serving plate.

Spread a little of the cream mixture on the plate. Stand ladyfingers around the edge of the springform ring. Lay ladyfingers onto the plate. Brush with a little coffee.

Scoop 1/2 the cream mixture on top of the ladyfingers.

Add the remaining ladyfingers. Brush with coffee (or see Elizabeth's comments below).

Top with the remaining cream mixture.

Dust with cocoa powder. Refrigerate for at least 2 hours before serving. To serve, gently remove the springform ring. Ladyfingers on the sides should be stuck to the filling.

If for some reason your tiramisu didn't setup properly, spoon into sorbet dishes and call it good!

And that is how you make a Kosher Classic Tiramisu!