Preheat oven to 350F. Saute onions, celery and garlic in butter until thoroughly cooked. Add soup, milk and cornstarch which has been diluted in 2 tablespoons water. Cook 10 minutes, stirring occasionally.
Add crawfish tails, green onions, parsley and cook until tender. Pour filling over bottom crust. Cover with top crust and cut several slits in top crust. Bake at 350F about 15 minutes. Reduce heat to 300F and bake until golden brown. Serve warm.
Cajun Country -- New Iberia, Louisiana