How to Make It
In a large enameled cast-iron casserole, melt 2 tablespoons of the butter. Season the chicken with salt and pepper and dust with flour. Add half of the chicken to the casserole and cook over moderately high heat, turning occasionally, until browned all over, about 7 minutes. Transfer to a plate. Repeat with the remaining 2 tablespoons of butter and chicken.
Add the onion, shallots, garlic and a generous pinch each of salt and pepper to the casserole and cook over moderately high heat, stirring occasionally, until softened, about 5 minutes. Add the wine and tomato paste and simmer until slightly reduced, 2 minutes. Add the tomatoes, stock, porcini, thyme and bay leaf and bring to a boil. Nestle the chicken in the sauce, cover and simmer over moderately low heat until nearly cooked, about 25 minutes. Stir in the cremini mushrooms and cook, uncovered, until the chicken is cooked through, about 12 minutes. Discard the thyme sprigs and bay leaf. Transfer the stew to plates, garnish with parsley and serve.