How to Decorate Cookies with Royal Icing

Royal icing is a simple mixture of powdered sugar, water and egg white or meringue powder that dries hard and smooth. It is what gives decorated sugar cookies their clean, glassy surfaces and sharp lines. Almost every technique comes down to one skill: getting the icing to the right consistency for the job.

This guide covers mixing and coloring, the difference between piping, outline and flood icing, how to fill a cookie without craters or overflow, and how long to dry before stacking or packing.

Mixing royal icing

Meringue powder is the easiest base: it is pasteurized, shelf-stable and consistent. Beat powdered sugar, meringue powder and water with a paddle on low to medium speed for 4 to 5 minutes, until thick, matte and holding stiff peaks. Raw egg white also works, but use pasteurized egg whites for icing that will not be cooked.

Keep icing covered at all times with plastic wrap pressed onto the surface or a damp towel over the bowl. Exposed icing crusts within minutes and the dry bits clog piping tips.

Choosing the right consistency

Decorators often describe consistency by how long a line drawn through the icing with a knife takes to vanish. Add water a few drops at a time and stir gently, rather than beating, to avoid whipping in air.

• Stiff: holds peaks; for piped flowers, leaves and gluing gingerbread houses
• Piping or outline: like toothpaste, a line closes in 20 seconds or more; for borders, lettering and fine detail
• Flood: like thick honey, a line closes in about 10 to 15 seconds; for filling large areas
• Many decorators use a single 15-second consistency for both outlining and flooding to save time

Coloring and filling bags

Use gel or paste food color; liquid color thins the icing and gives pale shades. Colors darken as icing dries, especially reds, blacks and navy, so mix them an hour or more ahead and aim slightly lighter than the final shade you want.

Fill piping bags or squeeze bottles about two-thirds full and twist the top closed. A coupler with a small round tip, such as a #2 or #3, gives control; tipless bags cut with a small opening work well for flooding.

Outlining and flooding

Start with completely cooled cookies. Hold the bag at a 45-degree angle and touch the tip to the cookie, then lift slightly and let the line of icing fall into place as you move, about 3 to 5 mm inside the edge. Touch down again to end the line.

Fill inside the outline with flood icing, working from the edges inward, and stop just short of the border; the icing will level out. Use a scribe tool or toothpick to push icing into corners and pop any air bubbles. Gently shake the cookie side to side to smooth the surface.

Wet-on-wet, layers and detail

For wet-on-wet designs, pipe dots or lines of a second color into the flood while it is still wet. They sink in flush with the surface. Drag a scribe through dots to make hearts or through lines to create marbled patterns.

For raised or adjacent sections, flood one area, let it crust for about an hour, then flood the neighbor. Fine details such as lettering, eyes or lace go on after the base has dried for several hours, using piping consistency icing.

Drying and storage

Dry decorated cookies in a single layer at room temperature, uncovered, for at least 8 hours and up to a day for thick flood work. A fan nearby can speed drying and give a shinier surface. Humid weather slows drying considerably.

Once fully hard, store cookies in an airtight container in single layers separated by parchment for up to about a week at room temperature. They can be frozen in airtight containers; thaw them in the closed container to keep condensation off the icing.

Common questions

Why does my icing have craters or sinkholes?

Small dips appear when flood icing is too thin or dries slowly over a small space, such as an eye. Use slightly thicker icing for small sections, pop air bubbles and dry the cookies under a fan for the first hour.

What causes color bleeding?

Dark colors bleed into light ones when icing is too thin or drying is slow. Let each color crust before piping a contrasting one next to it, and avoid very humid rooms.

Why do I see blotchy spots on dried icing?

Butter bleed happens when fat from the cookie seeps into the icing, often if cookies were iced while warm. Let cookies cool fully and consider a less buttery dough for heavily decorated sets.