For the cookies, preheat oven to 350˚F with the rack in the middle of the oven. Line two baking sheets with parchment paper.

Beat softened butter in the bowl of an electric mixer until soft and fluffy. Add powdered sugar and vanilla and beat until smooth.

Add flour and salt. Beat just until all flour is incorporated. Make sure there’s not dry flour at the bottom of the bowl.

Place dough onto a piece of plastic wrap and form into a disk. Wrap well and place in refrigerator for 15 minutes. (If you end up refrigerating more than 15 minutes, let dough sit out and warm up a bit before rolling. Otherwise it will crack when you try to roll it.)

Remove dough and unwrap. On a lightly floured surface roll out the dough into a ¼ inch (.6 cm) thick circle. I like to use ⅜ or ¼-inch dowels on either side of my dough as I roll it (pictured above in the post, the ¼ inch will be thinner). This keeps the dough at a perfect even thickness.

Shortbread cookies with keep in an airtight container for about a week or they can be frozen.

To make the glaze, combine powdered sugar, vanilla, almond extract and 3 tablespoons of the milk in a medium large bowl. Mix well and add more milk, one teaspoon at a time until a thick but drizzle-able glaze is formed. Transfer half of the glaze to a small bowl (like a soup size bowl). With a toothpick, add a small amount of gel food coloring and stir all through the icing in circular movements to form a swirly pattern. Don’t stir too much or the icing will become a solid color. Use a light hand with the gel food coloring. A little goes a long way!

Dip one cookie at a time into the glaze. Let the cookie sit on the top of the glaze and gently push down at all the edges to ensure the surface of the cookie is covered with the glaze. With your thumb and forefinger, pull the cookie out of the glaze and allow the excess icing to drip off. Then quickly flip the cookie right side up and give it a gentle jiggle to allow the glaze to flow evenly over the surface. Repeat with remaining cookies. Add more of the white glaze to the bowl when needed (stir well before adding). Use a toothpick to swirl more food coloring through the glaze any time the swirly effect is getting lost. You may need to add a few more drops of milk if the glaze gets too thick. Just stir it in well and add a little more food coloring to restore the swirly effect.

Allow the cookies to sit on a wire rack for a least one hour to “set” the icing. Once the icing is set, cookies can be stacked in an airtight container with wax paper or parchment paper between the layers.