Mix the margarine, sugar and vanilla sugar until frothy. Gradually add the eggs. Sift the flour, baking powder, and custard and fold in. Add milk as needed. Bake the waffles (about 6 pieces)
In the meantime, drain the plums. Mix half of the plum juice with the pudding powder. Heat the other half with the plums in a saucepan, thicken with the mixed pudding powder and bring to the boil. Season to taste with cinnamon.