Split bread in half lengthwise. Pull out some bread from center of each half, leaving a 1/2-inch shell. Beat cheeses and herbs with fork and spread mixture along length of both bread halves. Place a ribbon of pizza sauce and a single layer of onions over cheese mixture. Sprinkle with Parmesan and bake on baking sheet at 400 degrees for 30 minutes or until onion is tender and tips are slightly blackened, but crust is not too dark. Sprinkle with dry parsley flakes if desired. Cut crosswise into narrow strips. Makes 8 servings.