Paste food color creates hues that are bright and more vibrant than those produced by liquid food color. Look for paste food color in candy and cake-supply stores and in cookware stores.
Cookies bake evenly when they are of uniform thickness. Before cutting the cookies, use a ruler to check the thickness of the rolled dough.
To easily mix food color into dough, place the dough in a food storage plastic bag with the food color and knead it.
If you don't have pastry bags, you can snip away a corner of a food storage plastic bag and place the pastry tip in the corner.