Heat 2 Tbl of oil and the butter in a skillet. Add the chicken halves, and panfry until they are golden brown all over. Remove the chicken from the skillet.
Add the onion and garlic to the skillet, and fry over a medium heat until they begin to soften. Add the bell peppers and mushrooms and fry for 2-3 minutes. Add the tomatoes and season to taste. Transfer the vegetables to a casserole dish, and arrange the chicken on top of them.
Add the wine to the pan and bring to a boil. Pour the wine over the chicken. Cover the pan and cook in a preheated oven at 350°F for 50 minutes.
Add the olives to the casserole and mix them in . Pour in the cream, cover, and return to the oven for 10-20 minutes.
Meanwhile, bring a large pan of lightly salted water to a boil. Add the pasta and the remaining oil, and cook until the pasta is tender bur still firm to the bite. Drain the pasta well and transfer it to a serving dish.
Arrange the chicken on top of the pasta, spoon the sauce over the top, garnish with the parsley and serve immediately. Alternatively, place the pasta in a large serving bowl and serve it separately from the vegetables.