For the cookies:

1. Preheat oven to 375 degrees F.
2. In a mixing bowl, beat butter with electric mixer on medium speed for 30 seconds.
3. Add sugar and beat until combined.
4. Add egg and beat until combined.
5. Beat in as much flour as your can (mixture will be thick) and then stir in any remaining flour.
6. Divide dough in half.
7. On floured surface, roll half the dough at a time until ⅛ inch thick.
8. Cut out cookies with desired cookie cutters.
9. Re-roll trimmings and cut out more cookies.
10. Arrange on greased baking sheets and bake 6 to 10 minutes, depending on how wide and thick the cookies are.
11. Cool on rack.
12. Decorate with icing.

For the icing:

1. In a small mixing bowl, mix together 1 cup of the sugar and 2 tablespoons milk until smooth.
2. Divide icing into desired number of bowls (if making cookies with 4 different colors, divide icing into 4 bowls).
3. Add food coloring to each bowl, drop by drop, stirring to combine and until you get the desired color.
4. Spoon icing into separate baggies.
5. Squeeze icing in baggie down into one corner of baggie, twisting baggie to remove air bubbles.
6. With scissors, cut a tiny hole in the tip of each baggie.
7. Place cookies on flat surface on top of parchment paper, wax paper or aluminum foil.
8. Carefully outline each cookie with border color.
9. Allow cookies to dry to the touch (about 30 minutes).
10. Set remaining icing aside to decorate cookies further.
11. In another bowl, make more icing.
12. Mix together remaining 1 cup of sugar, this time with 3 tablespoons milk (this is for the “flooding” icing).
13. When bordered cookies have dried, “flood” the interior parts of each cookie with icing (you can use the baggie method or a spoon).
14. Allow cookies to dry again, this time probably an hour.
15. Finally, when the cookies with “flooding” icing are dry to the touch, decorate with lines, dots, zig-zags and squigglies using the leftover border icing (or make a new batch).
16. If “marbleizing” cookies, draw horizontal straight lines across each cookie with several different colors of icing.
17. Use a toothpick and draw vertical lines through the colored icing to create a wavy, marbleized look.
18. Allow finished cookies to dry overnight at least 12 hours (24 hours is ideal).