Cook a pudding from milk, sugar and pudding powder according to the instructions on the package. Let cool down. Then stir in the creme fraiche and egg liqueur.
Put the peaches in a colander and drain well. Collect the peach juice.
Roll out the puff pastry and cover it lengthways with the ladyfingers. Soak in peach juice. Spread the pudding over it. Dice the peaches and spread over them. Beat in the puff pastry, press firmly and brush with egg white.
Bake in the oven at 220 degrees for about 30 minutes.