In a large mixing bowl, whisk together all purpose flour, caster sugar, cornflour, and kosher salt.

Add the butter to the dry ingredients. With your fingertips, rub the mixture together until it resembles coarse breadcrumbs.

In a small bowl, whisk together egg and vanilla extract.

Form a well in the dry ingredients. Add the egg and use a fork to mix until a dry, clumpy dough forms.

With your hands, finish bringing the dough together until a soft dough forms.

Shape into a 7-inch disc. Wrap in clingfilm/plastic wrap and refrigerate, at 1 hour or overnight.

Line 2 half sheet rimmed baking trays, or 3-4 smaller trays, with parchment or a silicone mat. Set aside.

On a silicone rolling mat or lightly floured countertop, roll dough to 1/4-inch thickness.

With a 2-inch round cutter, cut dough into discs, then use a 1/2-inch round cutter to cut a hole in the middle of each. (I used the party ring cutter from this set of classic British biscuit cutters.)

Re-roll scraps and cut remaining cookies.

Arrange on prepared trays. (If using a single half sheet rimmed baking tray, I recommend starting with 24 cookies, then baking the rest in a second batch. Don’t overcrowd the cookies on the tray, and do not bake multiple trays at once.)

Freeze cookies on tray for 15 minutes. Meanwhile, preheat oven to 350° F / 176° C.

Bake in preheated oven for 13-15 minutes, or until very lightly golden brown around the edges.

Transfer to a wire rack and allow to cool completely.

Icing:

Line a half sheet rimmed tray with parchment, wax paper or clingfilm/plastic wrap. Sit a wire rack over top.

In a medium bowl, whisk together confectioner’s sugar, corn syrup, whole milk, and vanilla bean paste.

Divide icing into four small bowls. If necessary, add more confectioner’s sugar to adjust the consistency. The icing should be thick enough to hold its shape when piped, yet thin enough for dunking and drizzling.

Tint with pink, yellow, and purple food coloring. (I used Chefmaster’s Neon Brite line, but you can choose any colors you’d like.

Turn each cookie upside-down and dunk in the icing color of your choice. Lift upwards and allow the excess icing to drizzle back into the bowl.

Repeat with remaining cookies. As you dip, sit each cookie icing side up on prepared wire rack, allowing excess icing to drip onto the parchment-covered tray below.

Set aside and allow the icing to set, about 30 minutes.

Meanwhile, transfer remaining icing into disposable piping bags. (You will need a separate bag for each color).

Once cookie icing is firm to the touch, pipe contrasting zigzags over each cookie. (Note: If you want to achieve a “feathered” look, pipe the zigzags while the cookies are still wet, then use a fondant tool or toothpick to feather.)

Allow cookies to sit at room temperature until icing sets, about 5-10 minutes.

Store party rings in an airtight container, layered between sheets of parchment, for up to 5 days.