In bowl, combine turkey, 1 cup of the cheese, celery, green onion if using, cranberries, parsley, mayonnaise, mustard and black pepper. Mix well. Set aside.
Unroll the 2 packages of crescent rolls; separate into 16 triangles in a circle on a large pizza pan or stone with wide ends 3 inches from the edge of pizza pan and points towards the outside. Points will extend off the edge of the pan(depending on size). Arrange the remaining triangles in the center of the pan, matching wide ends with triangles already in placed. The points will overlap in center.
Using small rolling pin(or small round jar or drinking glass), roll over seams of triangles where wide ends meet, making a smooth surface for filling. Don't seal center triangles.
Using an ice cream scoop, scoop filling evenly over the dough in a continuous circle.
Beginning with the last triangle placed in center of pizza pan, bring point of triangle straight across filling. Next, bring point of the opposite outside triangle diagonally across filling, covering point of previous triangle. The filling will show.
Repeat, overlapping points of inside and outside triangles to form a wreath. Tuck the last end under first.
Brush top of wreath with egg white.
Sprinkle with remaining 1/4 cup cheese.
Bake 25-30 minutes or until golden brown. I always make this with the leftover turkey. My family requests it every year. Enjoy!