To "applique-ify" cookies, outline with the color desired for the stitches.
In this case, I used white glaze.
Flood with your choice of colors and patterns.
Once they've dried for at least an hour, add stitches around edges in same "thread" color.
For gingham, you'll need glaze in both a light and darker version of the color of choice, plus white.
So for this snowman, I used white as the base,
then added lines in both directions in my light color blue glaze.
While it was still wet, I added a dot of the darker blue at each cross point.
This was definitely my favorite patterned Christmas cookies of the season. :)