Melt the butter in a large saucepan, over medium heat. Add the onions, corn and crawfish and saute for about 3 to 4 minutes. Add the cream, broth and crabmeat and bring to a high simmer, but do not boil. Cook for about 10 minutes to meld flavors, then reduce the heat to low. Add the potatoes, green onions, cream cheese and cayenne pepper. Adjust the seasoning with salt and pepper, to taste.
To finish, stir in the 2 egg yolks, lime juice, chopped parsley and grated cheese. Ladle into serving bowls and serve. Great dish.