Preheat oven to 350F. Spray a baking sheet with olive oil spray.
In a bowl, combine the beef, seasoning, grated onion and egg white. Mix to combine.
Cut each pepper in half lengthwise and remove the seeds. Fill with the ground beef mixture, leaving the top flat.
Bake for 20 minutes or until the peppers have softened and the beef is cooked through. Top with cheese. Bake for additional 3-4 minutes. Top with chopped parsley (optional). Serve.