Cook pasta according to package directions. Meanwhile, in a small bowl, combine the flour, bouillon, garlic powder, parsley, oregano and pepper.
In a small nonstick skillet, saute the mushrooms, onion and red pepper in oil until tender. Stir in flour mixture. Gradually add milk. Bring to a boil; cook and stir for 2 minutes or until thickened. Stir in Parmesan cheese. Drain pasta; add to mushroom mixture and stir to coat.