Wash and cut the fennel bulbs, cut smaller if necessary. Chop the fennel greens and set aside. Now the water is brought to the boil with a little salt and the fennel pieces are cooked in it for about 3-4 minutes. Be careful not to overcook the vegetables!
Drain the fennel while collecting the cooking water.
Preheat the oven to approx. 200 ° C.
Now the flour is sweated in the hot oil in a saucepan and extinguished with 2-3 ladles of the fennel boiling water. Always stir well so that no lumps form and boil down to a thick sauce for about 10 minutes and season with salt, pepper and, if you like, with anise or fennel seeds.
Put the fennel in a baking dish, pour the sauce over it and bake in the oven for about 15 minutes.
Serve with the fennel greens when serving.
The gratin is good as a side dish, e.g. with cereal patties, potatoes or with steak, as a starter or main course.
If you use whole wheat flour, the sauce gets a very tasty, nutty taste. However, lumps are more likely to form here.
Variant:
Add parsnips, carrots, onions and mushrooms to the fennel, do not pre-cook the onions and mushrooms.