The ornamental design for an ediblecookiemask, as shown and described.
FIG. 1 is a front elevation view of a edible cookie mask showing my new design.
FIG. 2 is a rear elevational view thereof.
FIG. 3 is a left side elevational view thereof wherein the right side elevational view thereof is a mirror image of the left side elevational view.
FIG. 4 is a top elevational view thereof; and,
FIG. 5 is a bottom elevational view thereof.
The broken lines shown in the drawings are for the purpose of illustrating unclaimed portions of the edible cookie mask and form no part of the claimed design.