Saute beef, onion, green pepper and celery over medium-high heat until meat is browned and vegetables are tender.
Add tomatoes, tomato paste, mushrooms, parsley, salt, pepper, thyme, marjoram and rice.
Spoon mixture into 2-quart casserole.
Convection Bake at 325°F for 20 minutes.
Top with cheese and continue baking 5 minutes or until cheese is melted.