Remove the spines from the “cardons”, peel them slightly and cut them into 3 -4 cm long pieces. Boil them in salted water with a little bit of milk until soft, then drain (keep the broth). Saute butter and flour in a small frying pan until soft. Extinguish with milk and stir to make a light white sauce. Refine with cream and season with salt and a little freshly grated nutmeg. Butter a gratin dish and layer the “cardons” alternately with cheese. Cover with sauce. Bake at top heat until the surface changes color slightly. You can also gratinate the “cardons” with cream only (without bechamel sauce), if you have thick heavy cream available. This will make the dish even more delicate.