Best Sugar Cookie Icing Recipe for Hardening

Name: Best Sugar Cookie Icing Recipe for Hardening
Prep time: 15 min
Total time: 15 min
Cuisine: American
Ingredients: 2 cups powdered sugar; 2 tablespoons milk (more as needed); 2 tablespoons light corn syrup; 1/2 teaspoon vanilla extract or almond extract; Gel food coloring (optional)

March 30, 2025 by Emma

Jump to Recipe·3 from 4 reviews

Why You’ll Love This Recipe

This icing dries to a smooth, glossy finish, which makes it easy to decorate and stack cookies without worrying about smudges. It’s also customizable, so you can add different flavors or colors to match any event. The icing hardens to ensure your decorated cookies stay fresh and stunning for days.

Ingredients

2 cups powdered sugar
2 tablespoons milk (more as needed)
2 tablespoons light corn syrup
1/2 teaspoon vanilla extract or almond extract
Gel food coloring (optional)

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

Directions

In a medium-sized mixing bowl, whisk together the powdered sugar and milk until smooth. If the mixture is too thick, add more milk, a teaspoon at a time, until you reach the desired consistency.
Stir in the corn syrup and vanilla or almond extract. The corn syrup adds a glossy finish and helps the icing harden.
If you want to color the icing, add gel food coloring and mix until the color is evenly distributed.
Spread or pipe the icing onto cooled sugar cookies. For a smooth finish, gently tap the cookies on the countertop to help the icing settle.
Allow the cookies to sit at room temperature for several hours or overnight until the icing is fully dry and hardened.

Servings and Timing

Servings: This recipe is enough to decorate about 24-30 sugar cookies, depending on how thick the icing is applied.
Prep Time: 15 minutes
Setting Time: 2-4 hours (or overnight) for full hardening

Variations

Dairy-Free: Use almond milk or water instead of regular milk for a dairy-free option.
Flavored Icing: Try different extracts, such as lemon, peppermint, or almond, to create a unique twist.
Royal Icing Alternative: For firmer icing, add a tablespoon of meringue powder to the mixture.

Storage/Reheating

Refrigeration: Store leftover icing in an airtight container in the fridge for up to one week. Stir well before using again.
Freezing: This icing can be frozen for up to 3 months. Thaw it in the refrigerator and mix before use.
Decorated Cookies: Once the icing has hardened, store decorated cookies in an airtight container at room temperature for up to 5 days.

FAQs

Can I use this icing on other types of cookies?

Yes, this icing works great on various cookies like gingerbread, shortbread, and even snickerdoodles.

How can I thin the icing if it’s too thick?

Add a few drops of milk or water until the icing reaches the desired consistency.

Will this icing harden if I use it for intricate designs?

Yes, it hardens perfectly and allows for detailed designs without smudging.

Can I make this icing in advance?

Yes, you can prepare it up to a week ahead. Just store it in an airtight container in the fridge and stir before use.

How long does it take for the icing to harden?

The icing will typically start to set in 15 minutes and completely harden within 30 minutes, depending on the thickness of the icing.

Can I add multiple colors to the icing?

Yes, you can divide the icing into bowls and add different gel food colors to each for a variety of hues.

How can I make the icing glossy without corn syrup?

If you prefer not to use corn syrup, try using light corn syrup substitutes or honey, although it may slightly alter the texture.

Can I use powdered egg whites in this recipe?

For a firmer texture, you can incorporate powdered egg whites, making this recipe more like royal icing.

Will the icing stay soft after hardening?

No, once the icing hardens, it will remain crisp and firm, which makes it perfect for stacking or packaging cookies.

How do I avoid air bubbles in the icing?

When mixing the icing, stir gently and avoid overmixing to reduce air bubbles in the finished icing.

Conclusion

This sugar cookie icing recipe that hardens is a must-try for any cookie decorator. Its glossy finish, ease of use, and quick setting time make it the perfect choice for creating beautiful, long-lasting sugar cookies. Whether you’re making cookies for a special event or just because, this icing will elevate your baked goods to the next level.