Melt the butter. Put the biscuits in a freezer bag and crumble them with a cake roll. Mix the biscuits, except for something to decorate, and butter. Spread on the bottom of a springform pan (26 cm Ø) and press down to a firm base. Place the tin in a cool place. Wash, halve and stone the plums. Bring 350 ml juice to the boil.
Stir 50 ml juice, sugar and pudding powder until smooth. Bind the juice with it, bring to the boil again. Fold in the plums and chill. Pour warm, no longer hot plum pudding onto the crumb base and spread. Chill the cake for about 3 hours. Whip the cream until stiff, fill into a piping bag with a large star-shaped spout. Decorate the cake with cream and sprinkle with the remaining cookie crumbs
3 1/4 hours waiting time