To tint cookie dough, add gel paste food coloring after the dough has come together and knead in by hand. Gel coloring doesn't mix in like the liquid food coloring I grew up with, so kneading it is the way to go. For a really cool marble effect, knead only until there are swirls of color throughout your dough.
Once the flood icing was dried, I went back over the edges and borders of the cookies with some warmed corn syrup (meringue powder mixed with a little water works, too) using a small paintbrush and added some sparkling sugar. Do you know that October 30th is National Candy Corn Day? I learned that from A Dozen Eggs last week! Who knew? A great snack mix....candy corn and salted peanuts....yum!!!