Make room in your refrigerator for a baking sheet so the shaped cookies can chill for 20–30 minutes. Without chilling, the piped cookies will overspread. If you chill the dough prior to shaping, the dough will be too cold/stiff to pipe.

Line 2–3 large baking sheets with parchment paper or silicone baking mats, or leave unlined. If unlined, do not grease the pan.

In a large bowl, using a handheld mixer or a stand mixer fitted with a paddle attachment, beat the butter on medium-high speed until very soft and creamy, about 2 minutes. Add granulated sugar to the butter, and beat together on medium-high speed until smooth and creamed, another 2 minutes. (Here’s a helpful tutorial if you need guidance on how to cream butter and sugar.) Add the egg and vanilla, and beat on high speed until combined, about 1 minute. Scrape down the sides and up the bottom of the bowl and beat again as needed to combine.

On low speed, beat in the flour, cocoa powder, and salt. Turn up to high speed and beat until completely combined.

Warm the milk to about 150°F (66°C)—about 20 seconds in the microwave—then mix in the espresso powder until it dissolves. Add the warm espresso-milk mixture to the dough, and beat on medium speed. You want a dough that’s creamy and pipe-able (but still thick), so you may need another 1/2 Tablespoon of milk. (Tip: The more milk you add, the more the cookies will spread, so chilling in step 7 is imperative. I recommend keeping the amount of milk small and using a large enough piping tip, like the ones I suggest in the post above.)

Add your large piping tip to the piping bag. Spoon a little bit of dough into the piping bag and pipe a 1- to 2-inch swirl or line on the prepared baking sheet. The reason I suggest only a little bit of dough to start is because the dough may still be too thick to pipe. If it’s too thick, transfer that dough back to the mixing bowl and add another 1/2 Tablespoon of milk. If the dough is creamy enough to pipe, continue piping the dough in 1- to 2-inch swirls or lines, 3 inches apart on the baking sheet. If desired, place a maraschino cherry in the center of the swirl or sprinkle the dough with sprinkles and/or coarse sugar. (Tip: Since the dough is very thick and stiff, so the first few cookies you pipe will be the hardest. Don’t give up! It gets easier as you go along, as you handle the piping bag and the dough becomes more malleable.)

Transfer the baking sheet to the refrigerator and chill the shaped cookies for 20–30 minutes.

Meanwhile, preheat oven to 350°F (177°C).

Bake the chilled cookies for 12–15 minutes or until the edges seem set. The cookies will spread like all cookies do, but not completely lose their shape, especially if you refrigerated the shaped cookies. If the cookies are smaller, they will take closer to 12 minutes.

Remove from the oven and allow to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.

You can melt the chocolate in a double boiler or the microwave. If using the microwave: place the chopped chocolate in a medium heatproof bowl. Melt in 20-second increments in the microwave, stirring after each increment until completely melted and smooth. Dip the cookies in chocolate and top with sprinkles, if desired. Allow the chocolate to set completely at room temperature for about 1 hour or in the refrigerator for 20 minutes. Once set, you can stack, store, transport, and gift the cookies.

Cookies with chocolate or cherries stay fresh in an airtight container at room temperature for 4 days or in the refrigerator for up to 1 week. Cookies without chocolate or cherries stay fresh in an airtight container at room temperature for up to 1 week.