Spray a nonstick skillet with olive oil spray. Add the onion, carrots, and celery. Cook for 5 minutes, then add the minced garlic. Cook 1 minute.
Add the orzo and chicken broth. Bring to a boil, reduce heat to low and cover. Cook for 5 minutes, stirring occasionally.
Add broccoli and half and half. Cover and cook 4 minutes, stirring occasionally.
Remove the lid, stir in the cheese, salt, and pepper. Mix together until the cheese melts.