The easiest way would be to distract the person in possession of said cookie with this fabulous book:

Once that person begins reading all about Georgina and the irresistible dog in question, he/she will forget all about cookies. This book has already been nominated for a Texas Bluebonnet Award, is recommended by Parents Choice, and is a School Library Journal Best Book of 2007. I freely admit to having read this book sans cookies.
But looking at you, I sense your weakness. You’re probably the type who wants to have your cookie and eat it, too.
It’s a good thing the author herself, Barbara O’Connor, is here for the Cookie Party. She has brought one of her favorite recipes from The Silver Palate Cookbook (Workman, 1982). I recommend eating these very slowly,and savouring every crumb while reading Barbara’s book, to facilitate the ultimate canine cookie experience.
MOLASSES COOKIES

12 T (1-1/2 sticks) sweet butter
1 cup sugar
1/4 cup molasses
1 egg
1-3/4 cups flour
1/2 tsp ground cloves
1/2 tsp ground ginger
1 tsp ground cinnamon
1/2 tsp salt
1/2 tsp baking soda
Preheat oven to 350 degrees.
Melt butter, add sugar and molasses, and mix thoroughly. Lightly beat egg and add to butter mixture; blend well.
Sift flour with spices, salt and baking soda, and add to first mixture; mix. Batter will be wet.
Lay a sheet of foil on a cookie sheet. Drop tablespoons of cookie batter on foil, leaving inches between the cookies. These will spread during baking.
Bake until cookies start to darken, 8 to 10 minutes. Remove from oven while still soft. Let cool on foil.
(These are soft and chewy, and definitely worth stealing.)
TIP: I know you will like How to Steal a Dog so much, you will bark for more. But no need to beg, roll over, or steal. Just pre-order Barbara’s next book, coming in Spring 2008:

Leading a dog’s life? Break out of your kennel and join the Cookie Party!
Post your favorite recipe and leave the link in the comments, or email your recipe to me: readermail (at) jamakimrattigan (dot com)!