I make these semi-regularly because they are easy and they taste so good and everyone loves them. Also you can customize them for the holiday, or whatever, because sprinkles exist.
What you'll need:
1 package of white cake mix
1/2 cup vegetable oil
Preheat the oven to 350º F.
Mix ingredients in a large bowl. The texture should look like it does below, but it'll be really malleable and gooey to the touch.
Roll small pinches of cookie dough into balls and place on an un-greased cookie sheet. I lined the sheets with aluminum foil in hopes that it would aide in them baking evenly. It didn't make much of a difference, except in clean-up.
Start with 2 cups or so of powdered sugar, then add water* by the tablespoon until you get the consistency you're looking for. I've used thicker icing in the past, but this time I went with more of a drizzle (partially by accident, but it worked out). Add vanilla extract to taste (less is more).
*Edit: My mom suggests using milk instead of water!
I am pleased to say that I did not have a single cookie leftover from Messy's Hanukkah party last week. They were a hit. Enjoy!