This swirled rainbow frosting adds a bright, cheerful pop of color to any dessert. It’s perfect for birthday cakes, of course, but you can also use this rainbow icing for cupcakes, brownies, cookie sandwiches, and so much more.

Cupcake with swirled rainbow frosting and a rainbow piping bag next to it

🌈 How to Make Rainbow Icing

Is there anything better than a cupcake topped with a big, bold swirl of rainbow frosting? I’ve long been obsessed with bright colors and fun desserts, and rainbow-frosted cupcakes are the perfect marriage of the two!

The beauty of this rainbow icing technique is that it works for so many different events: kids and adult birthday parties, baby showers, spring and summer parties, St. Patrick’s Day, Pride events, and so many other occasions! It can be customized with any colors you’d like, and best of all, it looks complicated but is actually super easy to achieve. Read on to learn all my best tips and tricks for rainbow frosting!

If you’re looking for more rainbow desserts, you’ll love my Rainbow Cake with Rainbow Frosting, Rainbow Mousse Cake, or Pastel Rainbow Gelatin Cups. Be sure to check out these colorful birthday present mini cakes too!

Table of Contents

🧾 What You’ll Need

Here’s a short list of everything you’ll need to make rainbow-frosted cupcakes. (Shopping links are affiliate links)

Three cupcakes with colorful rainbow icing swirls

What Food Coloring To Use

I strongly recommend using gel food coloring over the liquid food coloring you can buy in a grocery store. Gel colors are more concentrated, so you won’t have to use as much coloring to get a bright, vibrant color. (Bonus: you can hopefully avoid the “food coloring aftertaste” if you use good-quality gel colors!) 

I recommend Americolor brand food coloring, or the Wilton ColorRight system. Here are the colors I used in these photos (these are affiliate links):

Three cupcakes with colorful rainbow frosting swirls

📋 Rainbow Frosting Instructions

Mixing bowl full of white frosting with a frosting-covered paddle lifted out of the bowl.

Step 1: Make your buttercream

The first step to making this colorful rainbow icing is to prepare your buttercream.  I’m sharing a delicious American buttercream frosting recipe in the recipe card down below, but you could also use Swiss Meringue Buttercream, my Easiest Swiss Meringue Buttercream, or a favorite recipe of your own.

For this technique, you can use any white frosting recipe with a pipeable consistency. You’ll want about 8 cups of frosting to frost 20-24 cupcakes.

Avoid this mistake:
Don’t use canned frosting purchased at the store, because it is too soft to pipe well and won’t make the gorgeous cupcake swirls we’re looking for.

Overhead shot of 6 bowls of colorful rainbow frosting grouped on a brown background.

Step 2: Color the Buttercream

The first thing to do is color the buttercream an assortment of rainbow colors (or whatever your color scheme is!)

Divide your white frosting equally between 6 bowls. No need to measure, eyeballing it is fine. Add a different color of gel food coloring to each bowl and stir well, adding more if necessary until you get a vibrant color.

Tip for red food coloring:

It is notoriously hard to get a bright red buttercream color! My best tips are to use a good-quality gel brand, and warm up a small amount (~2-3 TBSP) of buttercream in the microwave until warm but not hot. Mix a generous spoonful of red gel in with the warm buttercream, then mix THAT into the whole bowl. Starting with this small concentrated red portion helps the color disperse better throughout the batch. The color will also deepen as it sits, so if possible, mix up your red color the day before you need it so it has time to deepen.

Overhead shot of clear piping bags filled with colorful rainbow buttercream

Step 3: Put the Buttercream in Piping Bags

Place each color of frosting into its own piping bag, and snip a 1/2-inch opening in the end of each bag. No piping bags? No problem! You can substitute gallon-sized zip-top bags with a hole snipped in the corner instead.

Six stripes of colorful rainbow frosting on plastic wrap

Step 4: Pipe stripes of colors

Lay out a piece of plastic wrap on your counter. Start by piping a long line of red food coloring on the plastic wrap. Leave a margin of a few inches from the sides and bottom of the wrap. Next, pipe the orange frosting right next to the red.

Continue to pipe the colors in a row on the plastic wrap. Depending on how thick you pipe them, you can either fit one line of each color on the wrap, or repeat the pattern and make 12 stripes. Just make sure you leave a margin and don’t go all the way to the edge of the plastic wrap.

Rolling up rainbow frosting in plastic wrap

Step 5: Roll up the plastic wrap

Now, fold the plastic wrap over lengthwise and roll the frosting into a cylinder. Grasp the ends of the plastic wrap in each hand, and twirl it quickly so the frosting is burrito-shaped and the ends of the plastic are tightly twisted.

Hands holding piping bag with rainbow frosting inside

Step 6: Place the rainbow frosting in a piping bag

Fit a piping bag with a large star tip – I like the size of Ateco #849. Snip off one of the plastic wrap “tails,” and insert the frosting cylinder into the piping bag, snipped-side down.

Two cupcakes with tall swirls of colorful rainbow frosting

Your piping bag is now ready to go! Give it a little squeeze, because sometimes it takes a minute for all of the colors to come out together.

You’re now ready to make rainbow swirls on your cakescupcakes, or other desserts! Please share pictures if you give it a try, and don’t miss these other fun rainbow desserts!

Rainbow cake with a rainbow cake topper, cut open to reveal stripes of rainbow buttercream inside.

Rainbow Cake with Rainbow Frosting

This gorgeous Rainbow Cake has a surprise inside! Underneath the fluffy white cloud-like frosting are bright stripes of rainbow buttercream frosting. Make it for a special birthday, party, or St. Patrick’s Day!
View Recipe
Gold-Topped Rainbow Cake on a white cake stand in front of colorful bunting in the background.

Gold-Topped Rainbow Cake

If you’re looking for an over-the-top celebration cake, this Gold-Topped Rainbow Cake is for you! It features eight layers of lemon cake, seven layers of rainbow frosting, and one incredible assortment of edible golden goodies. Perfect for St. Patrick's Day or any big party!
View Recipe

If you try this tutorial, please let me know! Leave a ⭐️⭐️⭐️⭐️⭐️ rating on the recipe below and leave a comment, take a photo and tag me on Instagram @elabau, or use #sugarhero on IG!

Cupcake with colorful rainbow icing and a piping bag next to it

Rainbow Frosting

5 from 11 votes
This swirled rainbow frosting adds a bright, cheerful pop of color to any dessert. It’s perfect for birthday cakes, cupcakes, brownies, cookie sandwiches, and so much more.
Prep30 minutes
Total30 minutes
Yields18 servings

Ingredients

  • 4 TBSP milk, at room temperature
  • 1 TBSP vanilla extract, or other flavoring
  • ½ tsp salt
  • 8 oz unsalted butter, at room temperature
  • 8 oz shortening, can replace with equal amount butter if desired
  • 28 oz powdered sugar, (7 cups), sifted
  • Gel food coloring in six rainbow colors, I recommend Americolor

Instructions 

  • Combine the milk, vanilla extract, and salt in a small bowl, and stir them together to dissolve the salt and set aside.
  • Place the butter in a stand mixer fitted with a paddle attachment. Mix for 2 minutes on medium speed, until the butter is lighter in color and creamy. Scrape the bottom and sides of the bowl.
  • Add the shortening and the milk mixture, and use a splatter guard over your bowl or place a towel over the top of the mixer to prevent splatters. Run the mixer on low until the liquid starts to incorporate, then turn it to medium until everything is well-mixed and smooth (20-30 seconds). Scrape down the bowl again.
  • Keep the towel over the mixer, leaving only a small opening in front, turn the mixer to low, and add the sugar to the bowl in a steady stream. Once all of the sugar is incorporated, scrape down the bottom and sides of the bowl, and turn the mixer to medium-low for 30 seconds to mix the frosting well.
  • Divide the frosting equally between 6 bowls. Add a different color of gel food coloring to each bowl and stir well, adding more if necessary until you get a vibrant color. Place each color of frosting into its own piping bag, and snip a 1/2-inch opening in the end of each bag.
  • Lay out a piece of plastic wrap about 16 inches long. Start by piping a long line of red food coloring on the plastic wrap. Leave a margin of a few inches from the sides and bottom of the wrap.
  • Next, pipe the orange frosting right next to the red, and continue to pipe each color in a line. Depending on how thick you pipe them, you can either fit one line of each color on the wrap, or repeat the pattern and make 12 stripes. Just make sure you leave a margin and don't go all the way to the edge of the plastic wrap. (If you have extra colors left over, you can do this a second time to make another rainbow piping bag.)
  • Now, fold the plastic wrap over lengthwise and roll the frosting into a cylinder. Grasp the ends of the plastic wrap in each hand, and twirl it quickly so the frosting is burrito-shaped and the ends of the plastic are tightly twisted.
  • Fit a piping bag with a large star tip. Snip off one of the plastic wrap “tails," and insert the frosting cylinder into the piping bag, snipped-side down.
  • Squeeze the bag for a moment until all of the colors come out together, then your rainbow piping bag is ready! This recipe makes enough to frost 18 cupcakes with large swirls, or 24-28 cupcakes with small single-layer swirls.

Video

Recipe Notes

This recipe makes enough to frost 18 cupcakes with large swirls, or 24-28 cupcakes with small single-layer swirls.

Measuring Tips

Our recipes are developed using weight measurements, and we highly recommend using a kitchen scale for baking whenever possible. However, if you prefer to use cups, volume measurements are provided as well. PLEASE NOTE: the adage “8 oz = 1 cup” is NOT true when speaking about weight, so don’t be concerned if the measurements don’t fit this formula.

Want to learn more about baking measurements and conversion?

Nutrition

Calories: 377kcal | Carbohydrates: 44g | Protein: 1g | Fat: 23g | Saturated Fat: 10g | Trans Fat: 2g | Cholesterol: 27mg | Sodium: 69mg | Potassium: 10mg | Sugar: 43g | Vitamin A: 321IU | Calcium: 8mg | Iron: 1mg
Tried this recipe?Snap a pic and hashtag it #SugarHero. We love to see your creations on our Instagram @elabau.
Colorful Rainbow Cupcake Frosting picture with text overlay for Pinterest
Four photo square collage.

🌈 COLORFUL RAINBOW DESSERTS 🌈

We’ve rounded up 23 of our FAVORITE rainbow dessert recipes & ideas that are sure to make you smile — click here to get all the recipes!


Meet Elizabeth!

Hi, I’m Elizabeth — a trained pastry chef, cookbook author, video instructor, and your new Baking BFF! I’m going to teach you everything you need to know to be a sugar hero. ❤️

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19 Comments

    1. Hah, the great thing about rainbow frosting is that even when it doesn’t turn out perfectly, it still tastes great. 😀 Thanks Jacqueline!

  1. Such a fun and easy treat that does not disappoint! Enjoyed making these with my kids this afternoon; exactly what I needed to cure my sweet tooth!