Ingredients (20 pieces):

Dough:
200 g icing sugar
200 g butter
4 eggs
250 g flour
2 level teaspoons baking powder
1 pinch of salt
Lemon or orange zest

Topping:
100 g plum jam
1 kg rhubarb
50 g walnuts

Crumble:
75 g butter
75 g flour
50 g grated walnuts
100 g granulated sugar
1 pinch of salt

Preparation:
Preheat oven to 180 °C (fan oven). Strain the plum jam very finely. For the crumble mixture, melt the butter and leave to cool until lukewarm. Mix with the flour, grated walnuts, sugar and salt in a bowl, crumble into crumbles with your hands and chill. Cut off the ends of the rhubarb. Wash, dry and peel the stalks. Divide the thick stalks lengthways and cut into pieces approx. 5 cm long. For the batter, beat the butter and sugar until the sugar has dissolved. Add one egg at a time and mix thoroughly. Mix the flour, baking powder and salt and add to the egg mixture together with the lemon or orange zest and mix.
Spread the dough evenly on a greased baking tray and spread a thin layer of plum jam on top.
Spread the rhubarb, chopped walnuts and crumble mixture over the dough. Bake the cake in the middle of the oven for approx. 35-40 minutes until golden brown. Remove from the oven, leave to cool and serve.

Tip:
Add rhubarb and berry ragout as a flavoursome garnish.