Preheat oven to 400 degrees. Place all vegetables in a large bowl. Drizzle with olive oil and sprinkle with seasoning and oregano (and Parmesan if used). Stir till well coated. (May also mix this in a plastic bag if desired.)
Place in a greased metal baking pan. Bake for 30-35 minutes, stirring about 4 times during cooking. Serve immediately.