Preheat oven to 375F. Saute onions and celery in butter until onions are clear. Blend flour in well with mixture. Pour the milk gradually, stirring constantly. Add egg yolks, salt, red and black pepper. Cook for 5 minutes. Put crawfish in bowl suitable for mixing and pour the cooked sauce over the crawfish. Blend well and then transfer into a lightly greased casserole. Sprinkle with cheese. Bake for 10-15 minutes or until light brown.
Cajun Country -- New Iberia, Louisiana