1. Cook pasta according to package directions; add vegetables during last 2 minutes of cooking. Drain.
2. Gently toss pasta mixture in large bowl with shredded cheeses, 2 1/2 Tbsp Parmesan cheese and butter.
3. Turn into large casserole dish. Sprinkle top with remaining Parmesan cheese.
4. Bake in 450* F. oven 5 minutes or until cheese melts.