Knead flour, sugar, salt and cold butter in flakes to a smooth dough. If necessary, add about 1 tablespoon of ice-cold water. Cover the dough and chill for about 30 minutes.
Mix the marzipan, icing sugar and egg yolks to a smooth mixture. Pour into a piping bag with star-shaped spout. Roll out the short pastry on a floured work surface to a thickness of approx. 3 mm. Cut out 6 circles (about 8 cm Ø).
Place carefully on a baking tray lined with baking paper. Spray a wreath from the marzipan mixture onto the edge of the cookies. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 10-15 minutes.
Take out and let it cool down on a cake rack. Wash, halve and core the grapes. Drain the mandarins. Cover cakelets with fruit. Heat jam. Glaze the grapes and mandarins with it.
Allow to dry. Serve with whipped cream.