Traditional Tiramisu

If using fresh ladyfingers, toast in a medium oven until they are dried and light golden but not overly browned. Cool.
Combine the espresso and coffee liquor and set aside.
Combine the mascarpone, vanilla and Marsala in a large bowl and beat until smooth and creamy.
In a medium to large double boiler or nesting bowls, beat the eggs yolks and 3 tablespoons of sugar together until very smooth and lemon-colored. Set over a hot water bath and whip for 5 minutes until the eggs are light and foamy. Remove from the heat and immediately add the mascarpone mixture. Mix until smooth and then set aside.
In a clean bowl, whip the cream until it forms stiff peaks. Fold 1/2 cup of the mascarpone mixture into the whipped cream. Then fold the whipped cream into the remaining mascarpone mixture.
Whip the egg whites and salt until foamy, then add the remaining sugar. Continue to whip until the whites are glossy and slightly dry. Gently mix into the mascarpone/cream mixture.
Moisten half of the ladyfingers, one at a time, with espresso and place in the bottom of a pan - keeping them close together as possible. Top with half of the mascarpone mixture, spreading it evenly over the moistened cookies. Top with the rest of the ladyfingers, dipping each in the espresso and then topping with the remaining mascarpone mixture, spreading evenly. Sprinkle generously with cocoa powder. Refrigerate, uncovered, for at least 2-4 hours, then serve in squares.