1 Heat oil in a cast-iron casserole dish over medium heat and sauté onions and garlic for 5 minutes. Transfer to a bowl. Dust chicken in flour and sauté for 5–7 minutes until browned. Return onions to casserole dish and season. Add tomatoes, tomato purée, herbs and spices, stir well and cook for 10 minutes. Season, add wine and vinegar, then simmer for 1 hour until chicken is tender and sauce has thickened.