For the coffee syrup:
In a shallow bowl, combine hot coffee, 2 tablespoons sugar, and liqueur. Mix until sugar dissolves. Set aside to cool.
Assemble tiramisu:
Quickly dip ladyfingers (less than a second) into the coffee syrup and line them in one layer in an 8-inch baking dish. If necessary, break a few ladyfingers to fit them in the dish. Spoon half of the filling over the ladyfingers and smooth the top. Repeat with a second layer of coffee-dipped ladyfingers, then with the rest of the cream. Cover and refrigerate for at least 6 hours or up to 2 days. I don’t suggest freezing tiramisu since it will ruin its texture. Right before serving, dust the top with cocoa powder or grated chocolate. Serve cold.
*If you prefer to use egg whites instead of heavy cream, simply omit the cream and use 3 egg whites instead. Whisk them using an electric mixer until stiff peaks form, then fold them into the mascarpone-egg yolk mixture. If you use raw egg whites, be sure to use the freshest eggs possible with intact shells. You can also cook them over a double boiler, whisking the eggs constantly so they don't scramble until they are hot. Then, transfer them to a mixer with a whisk attachment and whip until stiff peaks form.