The Cook's Illustrated recipe comes with the frosting - you just spread it around with
the back of a spoon - occasionally it ran over a bit, but not bad at all. I put the icing in a ziploc sandwich bag and cut off the corner, then squeezed some on a few cookies at a time, then used the spoon to spread. It evens out quite beautifully. Once that dried sufficiently, I piped on designs - for the white-on-white effect.
Here's the recipe:
Glazed Butter Cookies
Cook’s Illustrated. Published November 1, 2003
Makes thirty-six to forty 2 1/2-inch cookies (2 dozen 4” cookies).
If you cannot find superfine sugar, you can obtain a close approximation by processing regular granulated sugar in a food processor for about 20 seconds (which is what I did). If desired, the cookies can be finished with sprinkles or other decorations immediately after glazing.
Butter Cookie Dough
2-1/2 cups unbleached all-purpose flour (12 1/2 ounces)
3/4 cup superfine sugar (5 1/2 ounces)
1/4 teaspoon table salt
16 tablespoons unsalted butter (2 sticks) cut into sixteen 1/2” pieces, at cool room temperature (about 65 deg)
2 teaspoons vanilla extract
2tablespoons cream cheese, at room temperature
Glaze
1 tablespoon cream cheese, at room temperature
3 tablespoons milk
1-1/2 cups confectioners' sugar (6 ounces)
Instructions
1. FOR THE COOKIES: In bowl of standing mixer fitted with flat beater, mix flour, sugar, and salt on low speed until combined, about 5 seconds. With mixer running on low, add butter 1 piece at a time; continue to mix until mixture looks crumbly and slightly wet, about 1 minute longer. Add vanilla and cream cheese and mix on low until dough just begins to form large clumps, about 30 seconds.
2. Remove bowl from mixer; knead dough by hand in bowl for 2 to 3 turns to form large cohesive mass. Turn out dough onto countertop; divide in half, pat into two 4-inch disks, wrap each in plastic, and refrigerate until they begin to firm up, 20 to 30 minutes. (Can be refrigerated up to 3 days or frozen up to 2 weeks; defrost in refrigerator before using.)
3. Adjust oven rack to middle position; heat oven to 375 degrees. Roll out 1 dough disk to even 1/8-inch thickness between 2 large sheets parchment paper; slide rolled dough on parchment onto baking sheet and chill until firm, about 10 minutes. Meanwhile, repeat with second disk.
4. Working with first portion of rolled dough, cut into desired shapes using cookie cutter(s) and place shapes on parchment-lined baking sheet, spacing them about 1 1/2 inches apart. Bake until light golden brown, about 10 minutes, rotating baking sheet halfway through baking time. Repeat with second portion of rolled dough. (Dough scraps can be patted together, chilled, and re-rolled once.) Cool cookies on wire rack to room temperature.
5. FOR THE GLAZE: Whisk cream cheese and 2 tablespoons milk in medium bowl until combined and no lumps remain. Whisk in confectioners' sugar until smooth, adding remaining milk as needed until glaze is thin enough to spread easily. Drizzle or spread scant teaspoon glaze with back of spoon onto each cooled cookie, as desired.