This dessert can be made with any amount of rhubarb - the ideal use of leftovers.
Clean the rhubarb, peel off the peel and cut into pieces approx. 2 cm in size.
Cook the rhubarb pieces together with the sugar and the water (take a little, the rhubarb draws water) for about 4-5 minutes.
Pour into a small ovenproof dish.
Mix the flour, sugar, vanilla sugar, salt and cinnamon in a bowl. Put the cold butter in flakes on top and quickly knead into crumble.
Place the crumble on the boiled rhubarb and bake in the preheated oven at 200 ° - or in the combi microwave at 180 ° convection with the grill switched on (level 2) - for about 12-15 minutes.