Rinse the chicken and cut it into portioned pieces. Heat the olive oil and fry the chicken meat until ready.
Remove and place it in a warm place, and in the same oil, fry the finely chopped onion. Put chicken in a deep fireproof dish, cover it with the sautéed onions, season with salt and black pepper on top and add the remaining vegetables, cut into medium-sized pieces.
Pour in some hot water, add the rosemary sprigs and sauté in a moderate oven under a lid until the vegetables become tender.