For the syrup mix coffee and liqueur. Dissolve 30 g sugar in it.
Separate eggs. Beat egg whites until stiff. Cream egg yolk and 50 g sugar with the whisk of the mixer. Stir in mascarpone by the spoonful and fold in 2 portions of egg white.
Break the cookies roughly. Divide half into four bowls (each approx. 9 cm Ø; 260 ml content) and sprinkle each with approx. 2 tbsp. coffee syrup. Spread half of the cream on top. Sprinkle with the remaining cookies and sprinkle with the remaining syrup. Spread the rest of the cream loosely.
Chill the tiramisu for at least 2 hours. Dust with cocoa before serving.