Press cookie dough into greased Shell Pan; bake, remove from pan, and while warm divide cookie in half lengthwise; cool.
On foil-covered board, position cookie pieces alongside cake. Pipe three Tip 18 scalloped outlines on cookie.
Ice pumpkin area smooth; pipe Tip 2B band on hat; add Tip 4 string outline around collar and eyes; pipe-in Tip 5 eyes and Tip 4 eyeballs.
Fill-in collar with Tip 18 stars; hat and turkey head with Tip 19 stars (overpipe eyebrow area) and add pull-out stars at forehead. Pipe Tip 12 hat buckle; add Tip 4 eyebrows and string bow.
Pipe Tip 2 lines on pumpkin and print Tip 2 message. Using heavy pressure and Tip 1A, pipe an elongated ball of icing for stem. Pipe Tip 2 vines and Tip 352 leaves.
Add beak and wattle: Using Tip 12 and heavy pressure, pipe a ball shape for bottom beak, tapering off the end as you gradually decrease pressure. Tuck tip into top and repeat, pulling out top beak. Using light pressure, pipe a line of icing alongside beak for wattle. Pipe Tip 352 pull-out wing feathers.