This creamy Turkey Tetrazzini casserole with mushrooms and peas recipe was named for a famous Soprano Luisa Tetrazzini in 1903..Its easy to make with leftover Thanksgiving turkey or chicken. With a rich parmesan cream sauce, this casserole will become your Favorite Servings: 6 to 8 servings Preheat oven to 400 degrees F. Butter a 4.8-qt (13×9) casserole dish.