Slice the cabbage, blanch in boiling water for 5 minutes and refresh under cold water. Crush the fennel seeds and the dill with a mortar and pestle, and add 1 tablespoon olive oil.
Slash the skin side of the fillets, spread them with the fennel and dill and season. Sauté the cabbage in olive oil, deglaze with white wine, add the cream and allow to reduce.