Peppermint-Spritz Cookies

Glaze: Whisk together confectioners' sugar and milk until smooth. Whisk in vanilla. Glaze can be stored at room temperature, with plastic wrap pressed directly on surface, up to 3 days; whisk before using. (Makes 2 cups.) Cookies: Preheat oven to 350 degrees. Beat butter with granulated sugar on medium-high speed until light and fluffy, about 3 minutes. Add yolk, flour, salt, peppermint extract, and milk; beat to combine. Fill a cookie press with dough and fit with a wreath disk. Press cookies directly onto unlined baking sheets. Bake, rotating sheets halfway through, until just golden on edges, 12 to 14 minutes. Transfer sheets to a wire rack; let cool completely. Working in batches, add a drop of food coloring to a small amount of glaze (about 1/4 cup); use a toothpick to swirl a tiny bit. Dip tops of cookies in glaze, then turn glaze-sides up and place on a wire rack set over a rimmed baking sheet to catch drips to set. (As you dip, colors will become more combined and no longer look like swirls; change to fresh glaze at this point.) For additional "swirls," dip a toothpick in red glaze and drizzle over cookies. Cookies can be stored in an airtight container at room temperature up to 3 days. Cook's Notes: If your cookie press has adjustable settings, set it at medium for the most defined wreath shape. If you don't have a press, you can form the dough into ropes and shape them into rings.