Sugar Cookie Icing

Sugar cookie icing is a simple 4-ingredient glaze made with sifted powdered sugar, whole milk, light corn syrup and almond extract (or clear vanilla extract). It pipes clean outlines, floods to a smooth shine, and dries hard enough to stack, pack and gift holiday cut-out cookies. For more holiday cookie trays, try these Christmas candy cane cookies and these 3-ingredient butter cookies.

Why You’ll Love This Sugar Cookie Icing

• Only 4 ingredients: powdered sugar, whole milk, light corn syrup and an extract make a full batch of decorating icing.
• Dries hard and glossy: once the cookies sit for 6 to 8 hours, or overnight, the surface sets firm enough to stack.
• Easy to tint: gel food coloring blends in without thinning the icing the way a liquid color can.
• Outline and flood from one batch: start thicker for borders, then loosen a portion with a few drops of milk for flooding.

What Is Sugar Cookie Icing?

Sugar cookie icing is a milk-and-corn-syrup glaze used to decorate cut-out cookies. It is not a buttercream, and it is not a royal icing made with egg whites. The powdered sugar gives the body, the milk loosens it to a pipeable texture, the light corn syrup adds shine and helps the surface dry to a firm shell, and the extract adds flavor. You can keep a portion thick for outlining and thin another portion for flooding, then tint each bowl with gel food coloring. For another sugar-cookie dessert, see this Christmas sugar cookie cheesecake. Store finished cookies in a cool, dry place; see this FDA guide to storing food safely.

Ingredients for Sugar Cookie Icing

• 3 cups powdered sugar, sifted
• 3 to 4 tablespoons whole milk
• 3 tablespoons light corn syrup
• 1/2 teaspoon almond extract, or clear vanilla extract
• gel food coloring, as desired

Ingredient Notes

The list follows a classic 4-ingredient decorating icing. All ingredients are generic, with no brand names. Gel food coloring is optional.

• Powdered sugar: 3 cups, sifted, so the icing stays smooth and free of lumps. Measure the sugar, then sift it into the bowl.
• Whole milk: start with 3 tablespoons and add more, a few drops at a time, up to 4 tablespoons, until you reach the consistency you need. Whole milk gives a little extra body; 2% milk also works.
• Light corn syrup: 3 tablespoons. This is what gives the icing its gloss and helps it dry to a firm, shiny shell. Use light corn syrup, not dark.
• Almond extract or clear vanilla extract: 1/2 teaspoon. Almond extract is the usual flavor for holiday cut-outs. Clear vanilla extract keeps white icing bright if you prefer a vanilla taste.
• Gel food coloring: a small amount of gel color tints the icing without adding much liquid. Start with a tiny drop, then stir well.

How to Make Sugar Cookie Icing

1. Sift the sugar: sift 3 cups of powdered sugar into a medium mixing bowl so there are no lumps.
2. Whisk in the milk: add 3 tablespoons of whole milk and whisk until the sugar is moistened and a thick paste forms. Scrape the bowl so no dry pockets remain.
3. Add the corn syrup and extract: whisk in 3 tablespoons of light corn syrup and 1/2 teaspoon of almond extract (or clear vanilla extract) until the icing is smooth and glossy.
4. Adjust the consistency: for outlining, the icing should hold a piped line and slowly ribbon back into the bowl. For flooding, stir in more milk a few drops at a time until a ribbon of icing smooths out on the surface in about 10 seconds. If it gets too thin, whisk in a little more sifted powdered sugar.
5. Divide and tint: spoon the icing into small bowls, one for each color. Stir gel food coloring into each bowl until the shade is even. Keep a bowl of white icing for snowflake details, swirls and borders. Press plastic wrap directly onto the surface of any icing you are not using right away so a crust does not form.
6. Outline, then flood: spoon the thicker icing into a piping bag or a small squeeze bottle and pipe a border around each cooled cookie. Fill the center with the thinner flood icing, then use a toothpick to nudge it into the corners and pop any air bubbles.
7. Decorate: add white piped details, such as snowflakes, swirls or stripes, and press on silver dragées or sprinkles while the surface is still wet so they stay in place.
8. Dry: leave the cookies in a single layer, uncovered, at room temperature for 6 to 8 hours, or overnight, until the sugar cookie icing is dry to the touch and firm enough to stack.

Hands-on time is about 20 minutes, plus decorating time. Drying takes 6 to 8 hours, or overnight. This batch is enough for about 2 to 3 dozen cut-out cookies, depending on how heavily you flood them.

Tips for the Best Sugar Cookie Icing

• Start thick, then thin: it is easier to loosen icing with a few drops of milk than to thicken a bowl that has gone too thin. Mix the base on the thicker side, then adjust each bowl.
• Sift the powdered sugar: even small lumps will clog a piping tip and leave bumps in a flooded cookie.
• Use gel color, not liquid: liquid coloring thins the icing and can keep it from drying hard. A little gel goes a long way.
• Work on fully cooled cookies: warm cookies will soften the icing and can cause colors to run.
• Give the icing a full dry: the surface may feel set after a couple of hours, but the center needs 6 to 8 hours, or overnight, before the cookies can be stacked or packed.

What to Serve With Sugar Cookie Icing

Sugar cookie icing belongs on plain cut-out sugar cookies, but a mixed holiday platter looks just as festive once the icing has hardened. Add a plate of these lemon almond cookies if you like the same almond flavor in a softer, un-iced cookie. Keep the iced cookies in a single layer until they are fully dry, then move them to a platter or a tin lined with parchment.

Variations

• Vanilla only: use clear vanilla extract in place of almond extract if you want a simple vanilla icing, or if almond flavor is not a good fit.
• Peppermint icing: swap the almond extract for peppermint extract, using a little less than the 1/2 teaspoon at first, then tasting.
• Outline only: skip the flood and pipe thick icing in simple lines, dots or lettering for a quicker tray.
• A soft frosting instead: this icing is meant to dry hard. If you want a fluffy frosting that stays soft, try this fluffy marshmallow buttercream frosting.

Storage

Let the sugar cookie icing dry completely, then store the cookies in a single layer, or stacked with parchment between the layers, in an airtight container at cool room temperature for a few days. See the FDA storage guide linked above and this Iowa State University Extension guide to storing decorated cookies for general advice on keeping decorated cookies dry. Avoid the refrigerator; extra humidity can dull the shine and soften the surface. Unused icing should be pressed with plastic wrap, covered tightly and kept in the refrigerator. Stir it well and adjust with a few drops of milk or a little sifted powdered sugar before using it again.

FAQ

What is sugar cookie icing?

Sugar cookie icing is a 4-ingredient decorating glaze made from sifted powdered sugar, whole milk, light corn syrup and almond extract or clear vanilla extract. It can be tinted with gel food coloring, piped as an outline or a flood, and left to dry hard and glossy.

How long does sugar cookie icing take to dry?

Plan on 6 to 8 hours, or overnight, at room temperature. The top may feel dry sooner, but the icing needs that full time to harden through so the cookies can be stacked or packed without smudging.

How do I make sugar cookie icing thicker or thinner?

For a thicker outline icing, whisk in a little more sifted powdered sugar. For a thinner flood icing, add whole milk a few drops at a time until a ribbon of icing smooths out on the surface in about 10 seconds. Adjust slowly so the bowl does not go too thin.

Can I make sugar cookie icing ahead of time?

Yes. Mix the icing, press plastic wrap directly onto the surface, cover the bowl and keep it in the refrigerator. When you are ready to decorate, stir it well, adjust with a few drops of milk or a little sifted powdered sugar, and tint as needed.

How should I store cookies decorated with sugar cookie icing?

Once the icing is fully dry, keep the cookies in an airtight container at cool room temperature, with parchment between any layers, for a few days. Do not refrigerate them, because humidity can soften the surface and dull the shine.