Cup of Yum
1. Whisk the dry ingredients together in a bowl and set aside.
2. Cream the butter, sugar, and vanilla together, scraping down the bowl to get everything combined. Blend in the egg.
3. Fold the dry ingredients into the wet to form a soft pliable dough.
4. While the dough is soft, roll it out to 1/4-1/3 inch thick. You can do this on a large sheet of parchment paper, with another sheet on top of the dough to prevent sticking. I found the top sheet unecessary, as a little dusting of flour worked fine.
5. Slice the parchment paper and dough onto a baking sheet and refrigerate for 30 minutes.
6. Preheat the oven to 350°F. Line 2 baking sheets with parchment paper.
7. Remove the cookie dough from the fridge and cut into rounds with a 2 1/2 inch cookie cutter. Place 2 inches apart on your cookie sheets and bake for 12-14 minutes. They will still be pale, but just starting to turn golden around the edges.
8. Cool the cookies on a rack until completely cooled before dipping.

marbled icing

Cup of Yum
1. Blend together the sugar, milk, water, and vanilla to make a smooth runny icing. You can do this in a food processor, or by hand. Divide the icing into 2 bowls and cover with plastic wrap. Let sit while the cookies cool, this will allow the bubbles to surface.
2. When the cookies are completely cooled, I suggest testing the consistency of your icing by dipping one cookie headfirst into the glaze, then flipping it over to set back on the rack. If the consistency seems fine** drop or drizzle a bit of each color across the surface of the white icing. Take a toothpick or chopstick and gently swirl the colors together. Be careful not to swirl too much, or the colors will blend and get muddy.
3. Dip each cookie headfirst into the marbled icing, lift straight up, and give it a twist to set it upright on the rack. As the colors get too muddy in your first bowl of icing, move on to the next.
4. Let the icing dry completely before serving or storing the cookies.