Season chicken with salt and pepper
Heat 2 tablespoons oil in a heavy cast iron skillet. Sear chicken on both sides until golden, about 3-4 minutes on each side. Remove from skillet and set aside.
Add the remaining oil to the pan. Sauté the onion until transparent, about 3-4 minutes. Add in garlic and cook until fragrant, about 30 seconds. Add the peppers, carrot, mushrooms, and herbs; cook for 5 minutes until vegetables begin to soften
Pour in the red sparkling jus, scraping up browned bits from the bottom of the skillet. Cook until it is reduced, about 2 minutes.
Add crushed tomatoes, tomato paste, Roma tomatoes, and chill flakes. Season with salt and pepper to your taste. Return chicken pieces to the skillet and continue to cook over the stovetop.
Mix all ingredients and cover with lid, reduce heat to low and allow to simmer while stirring occasionally for 40 minutes or until the meat falls off the bone. Add in the olives, and allow to simmer for a further 10 minutes.
Garnish with parsley and serve immediately.