Separate eggs. Beat 6 egg yolks, icing sugar and vanillin sugar with the whisk of the hand mixer until creamy. Fold the mascarpone into the egg yolk mixture. Beat the egg whites and 1 pinch of salt until stiff with the whisk of the hand mixer.
Fold the beaten egg white into the mascarpone cream in portions. Mix espresso and grappa.
Place half of the biscuits in a flat mould (approx. 16 x 27 cm) and sprinkle with half of the espresso mixture. Spread half of the mascarpone cream on the biscuit and smooth it down.
Spread the remaining biscuits on top and sprinkle with the rest of the espresso mixture. Spread the rest of the mascarpone cream on top and smooth it down. Chill the Tiramisu for about 3 hours. Clean, wash and halve the strawberries.
Dust Tiramisu with cocoa before serving and serve with strawberries.