Photo: Martin Poole
Heat the oil in a large ovenproof casserole and brown the chicken in batches until golden, removing to a plate as you go. Add the bacon for 2 minutes until golden, then transfer to the plate with the chicken. Brown the mushrooms, then add to the chicken.
Preheat the oven to 160°C, fan 140°C, gas 3. Add the onion and celery to the pan, cook for 10 minutes until soft, then add the garlic. Return the chicken, bacon and mushrooms to the pan. Add the wine and herbs, bring to the boil and simmer for 2 minutes. Addthe tomatoes, sugar and olives, stir and bring to the boil. Cover and transfer to the oven for 1 hour, until the chicken is tender.
Remove from the oven and season; take out the bay leaf and rosemary before serving.
For the gremolata, put half the parsley in a blender with the garlic, lemon zest and juice, capers and 3 tablespoons of the olive oil. Season and whiz until smooth. Add the remaining parsley and pulse (keep it chunky). Add the remaining olive oil and a little water.
Serve the cacciatore with the gremolata in a small bowl to spoon over.
Get ahead: make the casserole up to 2 days ahead, cool, cover and chill. Make the gremolata up to 30 minutes before serving. You can also freeze the cacciatore up to 2 months ahead. Make, cool; freeze in an airtight container. Defrost (48 hours in the fridge); heat at 180°C, fan 160°C, gas 4 for 45 minutes or until piping hot.