Wash the plums, drain, halve and stone them. Coarsely chop the walnuts. Cream fat, salt, 100 g sugar and vanillin sugar with the whisk of the hand mixer. Stir in 2 eggs one after the other.
Mix flour and baking powder, add in two portions and stir in. For the icing, mix double cream, 75 g sugar, 3 eggs and sauce powder. Mix in the nuts. Pour the dough into a greased pizza tray (30 cm Ø) sprinkled with flour, smooth it down.
Place the plums evenly in the saucepan and pour the glaze over them. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 45 minutes. Remove from the oven, place on a cake rack and allow to cool in the mould.
Whipped cream is delicious with it.