Sift your sugar: Add powdered sugar to a mixing bowl and sift to remove any lumps. This prevents clogged tips and grainy icing.

Whisk the base: Stir in 3 tablespoons milk, corn syrup, vanilla, almond extract, and salt. Whisk until smooth and glossy. If using meringue powder, whisk it in with the sugar before adding liquids.

Adjust thickness: For outline icing, aim for a thick, toothpaste-like consistency. If it’s too stiff, add milk by the 1/2 teaspoon. If too thin, whisk in a spoonful of powdered sugar.

Divide and color: Split icing into small bowls. Add gel color with a toothpick and mix well. Go slow—colors deepen as they sit.

Make flood icing: For filling in cookies, thin a portion of each color with a few drops of milk at a time. The sweet spot is the 10–12 second rule: when you drag a knife through the icing, the line should disappear in about 10–12 seconds.

Bag it up: Transfer outline icing to piping bags fitted with small round tips (#1–#3). Add flood icing to squeeze bottles or bags. Keep unused icing covered with plastic wrap touching the surface to prevent crusting.

Outline the cookies: Pipe a clean border around each cooled sugar cookie. Let it set for 5–10 minutes. This fence keeps flood icing from spilling over the edges.

Flood the centers: Fill with thin icing, using a scribe tool or toothpick to nudge icing into corners and pop air bubbles. Don’t overfill—icing should level out on its own.

Add details: Once the base is surface-dry (20–40 minutes), pipe details like polka dots, lines, or lettering with thicker icing. For layered designs, wait 1–2 hours so lower layers don’t dent.

Dry completely: Let decorated cookies dry uncovered at room temperature until firm, ideally 8–12 hours or overnight. Avoid humid spots and direct sunlight.