We claim the ornamental design for a cooking platter, as shown.
FIG. 1 is a perspective, front view of a cooking platter showing our new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a bottom plan view thereof; and,
FIG. 4 is a right side elevation view thereof.
The figures portion of the platter shown in broken lines form no part of the claimed ornamental design. Similarly, the top edge of the cooking platter is shown in broken lines and also forms no part of the claimed ornamental design.