In a large heavy-bottomed skillet, cook the chicken without fat over a fairly high heat, turning occasionally until golden brown. Using a slotted spoon, drain off any excess fat from the chicken and transfer to a flameproof casserole dish.

Heat the oil in the skillet over a medium heat. Add the onion, garlic, and bell pepper, and cook for 3 to 4 minutes. Transfer the vegetables to the casserole dish.

Add the orange peel and juice, chicken bouillon, chopped tomatoes, and sun-dried tomatoes to the casserole and stir well.

Bring to a boil, then cover the casserole with a lid and simmer very gently over a low heat for about 1 hour, stirring occasionally. Add the chopped thyme and black olives, then season to taste with salt and pepper.

Spoon the chicken casserole onto 4 warmed serving plates, garnish with orange peel and thyme, and serve with crusty bread.