Knead flour, fat, nuts, sugar, salt, 1 egg and vanilla sugar to a smooth dough. Cover and chill for about 30 minutes.
Clean, wash, halve and stone the plums. Roll out the dough thinly on a floured surface and cut out 6 circles (each approx. 15 cm Ø). Place in greased moulds with a removable base (approx. 12 cm Ø). Prick the dough more often with a fork. Spread 1 tsp. plum puree on each and cover with the plums
Dice marzipan. Mix with egg yolk and icing sugar until smooth. Pour the marzipan mixture into a piping bag with a star-shaped spout and squirt it onto the tartlets as a grid. Bake in a hot oven (electric cooker: 200 °C / convection oven: 175 °C / gas: level 3) for approx. 25 minutes
Warm up the jam, possibly pass through a sieve and stir until smooth. Spread the jam on the tartlets and bake for another 5 minutes. Leave to cool. Sprinkle with icing sugar as desired