Wash, clean and cut the strawberries into pieces. Mix with 30 g icing sugar and vinegar and chill for about 1 hour.
Mix mascarpone, quark, mineral water, 30 g icing sugar and vanillin sugar with the whisks of the hand mixer for about 30 seconds.
Line the bottom of a square mould (16 x 16 cm) with 6 1/2 sponge fingers. Spread 1/3 of the strawberries and strawberry vinegar stock on top and spread half of the cream on top. Lay a second layer of 6 1/2 sponge fingers on the cream.
Spread 1/3 of the strawberries and strawberry vinegar stock on top and spread the rest of the cream on top. Spread the last third of the strawberries and stock on top. Chill the tiramisu overnight.