Bring a large pot of lightly salted water to a boil. Cook pasta for 8 to 10 minutes, or until al dente; drain.
In a large skillet, brown beef over medium heat. Drain fat from pan, and transfer meat to a bowl. In the same skillet, cook onion and bell pepper in butter until tender. Stir in tomatoes, mushrooms, olives, and beef, and season with oregano. Simmer for 10 minutes.
Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 9x13 inch baking dish.
Arrange half of the cooked fettuccine in the prepared dish, top with half of the beef and vegetable mixture, and sprinkle with 1/2 cup of Cheddar cheese and 1/2 cup of mozzarella cheese. Repeat layers. Mix together soup and beef broth until smooth, and pour over casserole. Sprinkle with Parmesan cheese.
Bake in preheated oven for 30 to 35 minutes, or until heated through.
