1. Preheat the oven to 200 °C (th.7).
2. Prepare the crumble topping by mixing the flour, butter, sugar and cinnamon with your fingertips to obtain a sandy consistency.
3. Peel the bananas and cut them into slices of 3 cm. Mix them in with the vanilla sugar and the raisins.
4. Place them in the flat lid, spread out the crumble mixture over the bananas, making sure you cover the fruit completely. Place in the oven for 35 minutes.