Soak the berries in cold water for about 20 minutes. Wash the meat, dab dry and season with salt and pepper. Heat 2 tablespoons of oil in a large frying pan. Fry the meat for 10-12 minutes while turning.
Meanwhile wash and quarter the tomatoes. Clean and wash the salad. Coarsely chop nuts, roast them in a pan without fat, take them out. Peel and finely chop the onion. Drain berries in a sieve.
Season vinegar vigorously with salt, pepper and sugar. Add 3 tablespoons of oil drop by drop, stir in onion and berries. Mix salad, vinaigrette and tomatoes. Cut the meat into slices and arrange on plates with the salad, sprinkle with nuts.