Step 1 Preheat oven to 140°C. Place a large, flameproof casserole dish over high heat and spray with oil. Cook chicken in batches for 2 minutes, stirring occasionally, or until golden brown. Remove from dish and cover to keep warm.
Step 2 Return dish to medium heat. Spray with oil, add onion, pancetta, celery and carrot and cook, stirring occasionally, for 5 minutes, or until vegies are softened. Add garlic and oregano and cook, stirring, for 1 minute more. Add wine and simmer until reduced by at least half.
Step 3 Add tomatoes and 1 cup water, return chicken to dish and stir to combine. Bring to the boil, then cover and cook in oven for 1 hour. Add olives and butter beans, then return to oven for a further 30 minutes. Season to taste with black pepper and top with parsley.
Step 4 Serve chicken with mashed potato and steamed broccolini.