Roast the pine nuts in a pan without fat until golden brown, take them out. Clean the salad, wash thoroughly and drain. Peel onions and cut them lengthwise into fine strips. Wash the tomatoes, dab dry and cut in half.
Season 4 tablespoons of vinegar with salt, pepper and sugar, fold in 4 tablespoons of oil. Wash sage, dab dry, pluck leaves from the stalks and chop coarsely. Rinse liver and dab dry. Season with salt and pepper, turn lightly in flour, tap off.
Heat 2 tablespoons of oil in a large frying pan. Fry the liver for 3-4 minutes while turning. Add sage and fry briefly. Deglaze with 75 ml vinegar and 4 tbsp water, bring to the boil briefly. Season to taste with salt, pepper and sugar.
Mix onions, tomatoes, lettuce, pine nuts and vinaigrette in a bowl, arrange on plates. Add chicken liver. Ciabatta bread tastes good with it.