The ornamental design for a cookingdevice, as shown and described.
FIG. 1 is an end elevation view of a cooking device showing my new design.
FIG. 2 is an opposite end elevation view thereof.
FIG. 3 is a right side elevation view thereof.
FIG. 4 is a left side elevation view thereof.
FIG. 5 is a top view thereof.
FIG. 6 is a bottom view thereof; and,
FIG. 7 is a perspective view of the cooking device of FIG. 1.
The cooking device is shown with symbolic breaks in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design.