Take the puff pastry out of the refrigerator and let it rest at room temperature for about 10 minutes. Drain the apricots and cut the apricot halves in half.
Mix flour and sugar in a bowl. Coarsely grate the marzipan and add to the flour mixture together with the butter in flakes. Knead everything first with the dough hooks of the hand mixer and then briefly with your hands to form crumbles.
Unroll the puff pastry together with the baking paper and place it on a baking tray. Spread the edges on both long sides with cold water about 3 cm wide, fold over towards the middle and press down lightly.
Mix the jelly and spread a thin layer on the puff pastry strip. Place the apricots on top and sprinkle the marzipan crumbles on top and on the edges of the pastry, rubbing between your fingers.
Bake in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for approx. 30 minutes. Let it cool down on the baking tray. Dust with icing sugar and cut into strips.