Wash the meat, dab dry. Wash the thyme, dab dry, put some aside for garnishing, dab off the rest. Heat oil in a pan. Fry the meat for about 2 minutes on each side. Season with salt and pepper.
Sprinkle the fillets with thyme and remove. Let them cool down, put frying fat aside. Soak gelatine in cold water, squeeze out and dissolve carefully. Stir in port wine. Put the medallions in the freezer for about 10 minutes and take them out. Carefully spread the port wine mixture over the medallions with a spoon and chill. Wash and clean the salads, pluck small and drain well. Whisk frying fat with vinegar. Season with salt, pepper and sugar.
Carefully spread the port wine mixture over the medallions with a spoon and chill. Wash and clean the salads, pluck small and drain well. Whisk frying fat with vinegar. Season with salt, pepper and sugar. Arrange salad and medallions on plates. Drizzle with vinaigrette and garnish with thyme