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This Christmas cookie icing recipe that hardens is the secret weapon for beautifully decorated holiday cookies. It dries glossy, firm, and smooth, perfect for outlining, flooding, details, gingerbread houses, and any Christmas cutouts. And the best part? No raw egg whites. Just a few pantry ingredients and foolproof results.
Since you’re here for icing that actually sets, you’ll love my Cutout Sugar Cookies That Don’t Spread, my Christmas Marbled Sugar Cookies, Gingerbread Men Cookies, and this ultra-popular Christmas Fudge.
I made our traditional sugar cookies tonight and with this frosting recipe they turned out so much better! I love this recipe and the sheen of the hardened frosting on my sugar cookies. This had to be the easiest frosting recipe I’ve used and had a great taste too! Thank you for sharing. I will save it and use it again!
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I actually fell in love with this style of icing years ago at a hotel, they handed me a little welcome cookie, and the first thing I noticed was that the icing didn’t smear. I stacked it in a napkin, tossed it in my bag, eventually ate it… and it still held that glossy, picture-perfect finish.
From that moment I thought, okay, I need to recreate this at home, not just for myself, but so anyone can make sugar cookies that look bakery-quality without stressing about runny icing or raw egg whites.
After a lot of testing (and way too many cookies), this is the recipe that captures that same magical finish: smooth, shiny, and totally smudge-proof once it hardens.
Why This Is the Best Cookie Icing Recipe That Hardens
- Uses simple ingredients you already have at home
- Dries with a gorgeous glossy finish thanks to corn syrup
- Perfect consistency for outlining, flooding, or writing
- Beginner-friendly – no meringue powder, no egg whites, no stress
- Ideal for Christmas cookies, gingerbread houses, and every holiday decorating project
Ingredients You’ll Need
(Scroll to the recipe card for full measurements.)
- Powdered sugar (aka confectioners’ sugar)
- Corn syrup – gives the icing shine and structure
- Clear vanilla extract – for bright white icing
- Milk or water – adjust to reach your desired consistency
- Gel food coloring – vibrant color without thinning the icing
How to Make Sugar Cookie Icing That Hardens
- Mix the base: In a large bowl, whisk together powdered sugar, vanilla, milk, and corn syrup.
- Adjust consistency: Add tiny drops of milk to thin, or extra powdered sugar to thicken. For flooding, aim for it to be slightly runny. For outlines/details, aim for a thicker texture.
- Color the icing: Divide into bowls and tint each with gel food coloring.
- Decorate: Use squeeze bottles or piping bags with small tips. Let decorated cookies dry completely before stacking or packaging.
Recipe Tip For This Cookie Icing That Hardens
- Use powdered sugar made with tapioca starch instead of cornstarch, it blends smoother and eliminates that chalky aftertaste some icings get.
- Add liquid slowly. A few drops can take your icing from outline-thick to flooding-thin, so adjust in tiny increments.
- Stick to gel food coloring to avoid thinning the icing.
- Cover your bowls with a damp towel so the icing doesn’t crust while you work.
- Let cookies dry completely (6–24 hours depending on thickness) before stacking or packaging for crisp, smudge-free designs.
Frequently asked questions – FAQ
Store in a squeeze bottle or airtight container in the fridge for up to 3 days. Bring to room temperature before using.
Yes, but your icing won’t be bright white. It’s perfect if you plan to add food coloring anyway.
You can, but reduce the milk slightly since it adds extra liquid.
Add more powdered sugar until it thickens.
Try clear vanilla extract, almond extract, coconut extract, or lemon extract so the icing stays white.
Anywhere from 6–24 hours, depending on thickness and humidity.
Store fully dried cookies in an airtight container for up to 2 weeks. Separate layers with parchment to protect the designs.
Sugar cookie icing that hardens
Ingredients
- 2 cup powdered sugar
- 1 & 1/2 tbsp corn syrup
- 1/2 tsp vanilla extract
- 1 & 1/2 tbsp milk or water cold
- gel food coloring
Instructions
- Sift the powdered sugar in a medium/large bowl. Add in the corn syrup, vanilla extract, and milk or water. Stir vigorously until smooth.2 cup powdered sugar, 1 & 1/2 tbsp corn syrup, 1/2 tsp vanilla extract, 1 & 1/2 tbsp milk or water
- Add more milk is needed to get to your desired consistency. You want the icing to slowly fall off the spoon, leaving a pretty thick layer behind it.
- Divide the icing into multiple smaller bowls if making multiple different colored batches. Use to decorate cookies, let the icing set at room temperature before storing the cookies in an air tight container.gel food coloring
Nutrition information is automatically calculated, so should only be used as an approximation.
TF does this mean?
For flooding aim for it to be slightly runny and of outlines/details or for a thicker texture.
Thanks for catching that! There was definitely some text missing there, it should read: “For flooding, aim for it to be slightly runny. For outlines/details, aim for a thicker texture.”
I’ll update that right now so it makes sense. Sorry for the confusion!