Gingerbread Cookies:

In a large mixing bowl or the bowl of a stand mixer, cream butter and brown sugar until light and fluffy. Beat in the black treacle (or molasses), followed by the egg and milk, and mix on medium-high speed until well combined.

In a separate bowl, whisk flour, ginger, cinnamon, baking soda, cloves, nutmeg, and kosher salt.

Add dry ingredients to the butter mixture. Mix on medium-high speed until just combined.

Flatten dough into a large disc. Wrap in clingfilm/plastic wrap and refrigerate, at least four hours and up to two days.

Line a half-sheet rimmed baking tray with parchment or a silicone mat.

Unwrap the chilled dough and cut the disc in half. Place half of the dough on a floured surface.

Roll the dough to approximately 1/4-inch thickness.

With a snowflake or other metal cookie cutter, cut into desired shapes.

With a flat metal spatula, transfer cookies to prepared tray.

Re-roll scraps and cut remaining dough.

Chill cut cookies in the refrigerator for 30 minutes, or freeze for 15 minutes. (If your tray doesn’t fit in the refrigerator, you can stack the cut cookies between squares of parchment and chill the stacks.) Meanwhile, preheat oven to 350° F / 176° C.

Bake in preheated oven, one tray at a time, for 10 minutes (11-12 minutes for crispier cookies) or until very light brown around the edges.

Cool on tray for five minutes, then transfer to a wire rack to cool completely.

Royal Icing:

In a large mixing bowl or the bowl of a stand mixer, whip egg white to soft peaks.

Add confectioner’s sugar, 1/2 cup at a time, and mix on high speed until all sugar has been incorporated and meringue is thick and glossy, with stiff peaks. If necessary, add a bit more confectioner’s sugar to adjust the consistency. The royal icing should be thick, but pipeable.

With a flexible rubber spatula, scoop royal icing into a piping bag fitted small round tip. (I used a 1/16th-inch round tip.) Pipe as desired.

Allow decorated cookies to sit, uncovered, until icing sets. Store in an airtight container at room temperature for up to five days.