Drain the peaches, cut them into slices, clean the strawberries and cut them into slices as well.
Mix peach juice with peach liqueur (as you like) and possibly a little cognac.
Whip the marcarpone with quark and sugar, fold in the whipped cream, place the sponge fingers in the form (preferably in portion forms), drizzle with peach juice / liqueur. Spread the mascarpone cream on top, sprinkle the peaches and strawberries on top, cover with mascarpone, then another sponge finger (don`t forget to drizzle), mascarpone, fruit and another layer of mascarpone on top.
Garnish with strawberries, peach slices and possibly a sprig of mint.
Let it steep in the refrigerator for a few hours, take out of the refrigerator approx. 1 hour before consumption.