Clean, wash and cut the rhubarb into pieces of about 2 cm. Mix rhubarb, 75 g sugar and lemon juice in a roasting pan. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 15-20 minutes until the rhubarb is soft
Put flour, 100 g sugar, butter in flakes, salt and oat flakes in a large bowl. Mix with the dough hooks of the hand mixer. Then work into crumbles with your hands
Lightly press the rhubarb with a potato masher and place in 4 small or 1 large casserole dish. Sprinkle rhubarb with cinnamon and cover with crumbles. Bake in the preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas: level 3) for 35-45 minutes on the bottom shelf. If necessary, cover with aluminium foil about 10 minutes before the end of the baking time. Remove from the oven, place on a cake rack and allow to cool slightly. Delicious with vanilla ice cream