Preheat the oven to 200°C.
Cut plums in half and remove the seeds.
In a bowl, mix together flour and sugar. Add cold margarine in little pieces. Then mix the ingredients with your hands until you have an even crumble.
Put 100 g of the crumble into a second bowl and mix with icing sugar.
To the bigger part of the crumble add canola oil and white wine vinegar and knead to an even dough. Then roll it out to about 2 cm height and put on a baking sheet. Spread plums with the open side to the bottom over the dough. After that, add the other part of the crumble on top of the plums.
Bake for 25 minutes in the oven.