Roll out the chilled cookie dough to 1/4" thickness.
Have your child cut the dough with the table knife into domino-sized rectangles, approximately 1¼" x 2¼" each.
Transfer the cookie tiles to the baking sheet with a spatula.
Bake the cookies according to the recipe or package directions until golden at the edges, approximately 10 minutes.
While the cookies are still warm, have your child carefully cut off the edges of each one with a knife to create a sharper rectangle shape.
Allow the cookies to cool completely.
Help your child spread a smooth, thin layer of white frosting on top of each cookie. Place the cookies in a single layer on a flat plate or baking sheet.
Refrigerate the frosted cookies for 30-45 minutes to allow the frosting to set.
Have your child draw a line across the middle of each cookie with the black decorator's icing and add dots on either side in domino patterns.