1Saute onions and celery in butter. Blend in flour. Pour in milk, stirring constantly. Temper egg yolks by adding a little of the mixture to the eggs and stirring until well blended. Add back to the pan. Add salt and peppers. Cook 5 minutes on medium low heat. Put crab meat in large bowl pour cooked sauce over crab meat blending well. Add mushrooms.
2Place in a greased 9x13 pan. Sprinkle with cheese.
Bake 375*F for 10-15 minutes until cheese is lightly brown.
3** Note - Now that my family has grown by two son-in-laws that love to eat - I found I need to double this recipe... I doubled all ingredients except the crabmeat - I added 1 pound of boiled shrimp..