Put flour, 100 g sugar, salt, egg and butter in flakes into a mixing bowl and knead with the dough hooks of the hand mixer to a smooth dough. Wrap in cling film and chill for 30 minutes. Roll out short pastry on a floured work surface to a circle (32 cm Ø). Line a greased tart tin (26 cm Ø) dusted with flour, pressing the edge lightly. Place the mould in a cool place for about 15 minutes.
Place baking paper on the dough, add dried pulses. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 15 minutes. Carefully remove the baking paper with the pulses. Continue baking for approx. 5 minutes at the same temperature. Let it cool down. In the meantime, wash the plums, dab dry and stone them. Mix sour cream, 60 g sugar, starch and egg yolk. Cover the tart with plums and pour over the sour cream. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 30 minutes.
In the meantime, wash the plums, dab dry and stone them. Mix sour cream, 60 g sugar, starch and egg yolk. Cover the tart with plums and pour over the sour cream. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 30 minutes. Remove and let cool on a cake rack. Serve sprinkled with sugar crystals