Powdered sugarSift before using to prevent lumps clogging the piping tip1 cup (120 g)
Light corn syrupGives the icing shine, better texture, and prevents crystallization2 tsp
Almond extract (or vanilla extract)Can substitute with vanilla, lemon, orange blossom, rosewater, or coffee extract¼ tsp
Lemon juiceAdd a small drop for flavor~½ tspest.
MilkAdd gradually to adjust consistency, typically 1 teaspoon up to 1 tablespoon total1-4 tsp
Gel food coloringOptional, for coloring; gel-based is preferred as it won't thin the icing as much as water-based coloring~a few dropsest.
Sprinkles or sanding sugarOptional decorations, added while icing is still wet~as neededest.
Steps
1
Sift the powdered sugar into a medium bowl, pressing out any lumps with a spoon so the texture is smooth enough for piping.
2
Add the light corn syrup, which gives the icing its glossy finish, nice texture, and prevents sugar crystallization.
3
Stir in the almond extract (or your preferred flavoring) and a small drop of lemon juice.
4
Gradually mix in milk about 1 teaspoon at a time, checking the consistency each time, until the icing is smooth and falls in ribbons — this usually takes about 4 teaspoons total.
5
Gently mix with a spatula or whisk just until combined, without incorporating too much air. The consistency should be pipeable and self-leveling, but not too watery.
6
Divide the icing into batches and color each with gel food coloring as desired; if using water-based coloring, make the icing slightly thicker since it will thin more.
7
Fold the top of a piping bag over a glass to fill it easily, twist the top closed, and simply snip a small opening at the tip instead of using a piping tip.
8
Outline the edge of the cookie first, then fill in the center by moving back and forth, letting the icing flow and settle naturally without being too precise.
9
While the icing is still wet, add sprinkles or sanding sugar, which will stick in place as the icing acts like edible glue.
10
If layering multiple colors, let the first color set slightly before adding the next to avoid bleeding; use a toothpick to zigzag and smooth over any gaps.
11
Let decorated cookies sit undisturbed until fully dry — this can take up to 24 hours depending on humidity and icing thickness — and avoid stacking them before they set.