Preheat oven to 350F. Heat oil in skillet, then brown beef well. Drain and set aside. Simmer onions in boiling water 10 minutes. Drain. Reserve 1/2 cup of onion water. To this add cream of celery soup, garlic, mustard, pepper, cheese, salt, green onions, mix well. Pour into a 2-quart baking dish, lightly greased. Bake 25 minutes. Combine Parmesan cheese, bread crumbs and butter. Mix well. Remove dish from oven and turn on broil. Spread cheese mixture on casserole and broil until brown (about 2 minutes).
Cajun Country -- New Iberia, Louisiana