This recipe was developed for an italian uncle who found later in life that he was allergic to dairy, yet longed for a savory and creamy dairy-free turkey tetrazzini. Truly italian comfort food at its best, this dish is beautiful, simple and a family favorite. The casserole can be assembled, covered, and refrigerated up to four hours before baking. If you decide to do this, allow the tetrazzini to sit at room temperature for about 15 minutes before baking.