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These rainbow cookies are a big hit for birthday parties, celebrations, and sharing around the neighborhood. Made with royal icing and a sugar cookie base, they are a delicious mix of crunch and chewiness.
Rainbows always seem to be in.
Kids love them.
Adults love them.
We look outside after a storm for them.
Plenty of trends through the years have involved rainbows (complemented by things like unicorns and stars), and there is always room for some fun coloring.
In this rainbow cookie tutorial, I’ll teach you how to make rainbow cookies, how to decorate rainbow cookies, and tips for making royal icing and the sugar cookie dough.
What Type of Dough Do You Use?
When you’re making these cookies, you want to use a dough that will hold its shape.
That’s why I use a cut-out sugar cookie recipe, which doesn’t spread when it’s cooked in the oven.
If you’ve ever made something like chocolate chip cookies, you’ll know what it means for a cookie to spread – you put the dough in as a ball, and then it comes out a flatter circle of a cookie.
For these cookies, we don’t want any spread and want to actively avoid cookies spreading!
We want clean and clear edges, as that helps retain their rainbow shape and makes them look beautiful.
Follow the steps in the recipe exactly to ensure you have good results, and be aware that you may need to do a couple of test bakes as your oven might not be at the same temperature it says it is or you may have inadvertedly missed something out.
Better to find out before you go all the way as once it’s baked, there’s no going back!
Ingredients You’ll Need to Make the Dough
To make the cut-out sugar cookie dough for these rainbow cookies, you’ll need: flour, butter, granulated sugar, icing sugar, vanilla extract, salt, baking powder, and eggs.
The recipe will have instructions on what temperature the ingredients need to be at (for example, the butter should be at room temperature, not straight out of the fridge), and this helps to combine things in the right way – baking is a science!
Ingredients You’ll Need to Make the Royal Icing
The second part of the cookies is the royal icing.
There are a lot of different types of frosting including buttercream, glaze, etc.
Royal icing is one that gives you the ultimate decorating freedom, as you can get very detailed and it comes out wet by dries hard, freezing your design into place.
To make the royal icing recipe I use, you’ll need meringue powder, water, vanilla extract, and a lot of powdered sugar!
Other Tools You’ll Need to Make Rainbow Cookies
If it’s your first time baking or you need a refresh on what other tools you might need to make rainbow cookies, don’t forget…
- baking tray
- silicone baking mat – like this (makes sure the cookie doesn’t stick and keeps from spreading)
- a scribe or toothpick (to move around the icing into place if you make a mistake)
- red, orange, yellow, blue, green, and purple food coloring – I use gel food coloring like this as it’s better than liquid
- piping bags for the royal icing – these are the best
- rainbow cookie cutter – this one is great
Tips for Using Royal Icing on Rainbow Cookies
Piping with royal icing can be intimidating at first, but it’s easy once you get the hang of it.
These cookies are easy to do for beginners as well as the detail isn’t too intricate.
When piping, always hold your tip about an inch away from the cookie and let the icing drop down instead of actually feeling like you’re placing the icing on the cookie with the tip right next to it.
It feels like the closer you have the tip to the cookie, the more control you’ll have, but it’s the opposite.
For these cookies, I made my royal icing very stiff and did not use the “outline and flood” method of royal icing.
Instead, I just piped out each of the rainbow layers and created a more 3D version of a rainbow.
I found that this was an easier way to create a rainbow where the colors didn’t bleed into each other.
For the white icing, I did the same with by making a very stiff royal icing and a larger opening in the piping bag to pipe little clouds all around.
How to Mix Color into Royal Icing
You want to mix some color into the royal icing to make your rainbow colors – red, orange, green, blue, and purple
To do this, separate some icing into a bowl and start by adding drops of either your liquid or gel food coloring.
I much prefer gel food coloring for a deeper color, but you can use liquid if it’s all you have.
You just want to make sure you’re checking the consistency when you’re doing it and not letting it get too runny.
Obviously these rainbows do require a lot of different color mixing, but it will be worth it in the end.
How to Decorate Rainbow Cookies
Once you have all of your icing mixed and it’s very stiff so that it won’t go anywhere once you pipe it on, prepare by piping your first color, red, on top of the rainbow.
I waited about 30 minutes between piping each color, and I did all of the colors at the same time, ie, I piped all of the reds on all of my rainbow cookies and then did all of the oranges, etc.
This saved a lot of time and gave time to let each layer set.
Carry on doing the orange, then the rest of the colors in turn until you run out of room.
Give this 30 minutes or so to set, and then come in with your white icing and create little clouds at the bottom of each rainbow end.
This is a great chance to cover up any imperfections at the end of the rainbows, as you want it to cover up the ends of the rainbow anyway and appear as if the rainbow is sitting in the clouds.
Let it dry for a good 8 to 10 hours, and then you can package them or deliver them as needed.
