Soak the porcini mushrooms in half of the broth for 20 minutes. In the meantime, heat the oil. Add the onion and cook until it becomes soft. Add the chicken pieces and fry until evenly browned, adding the garlic towards the end. Pour in the wine and simmer for 2-5 minutes. Mix in the rest of the broth, bouquet garni and tomatoes and let simmer.
Remove the mushrooms from the broth, chop them and add to the saucepan with the broth poured through a sieve and salt and pepper. With the lid on, simmer gently for about 40 minutes.
Lift the chicken into a preheated serving bowl. Reduce the cooking liquid until a light sauce is formed. Pour over the chicken and sprinkle with the coriander.