Rainbow Swirl Frosting

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Learn how to make Rainbow Frosting in a swirl pattern for cupcakes, cakes, and cookies! I’m sharing all of my secrets for the best rainbow frosting – it’s so pretty and easy to make. I can’t get over how pretty this is – and it tastes SO MUCH BETTER than store bought frosting!

vanilla cupcakes with rainbow colored frosting on top.

Rainbow Frosting Cupcakes

One of my favorite frosting techniques is rainbow swirl frosting, and I think you’ll be surprised how easy it is to do. Next to sprinkles, swirl frosting is one of my favorite ways to decorate birthday cakes, rainbow cupcakes, and cookies. You can use any colors you want to dye frosting – I’ve used this same method to make Unicorn Cupcakes!

Make my rainbow cake with this colorful frosting and you’ve got an explosion of rainbows for any party. You can use my homemade American buttercream recipe or even cream cheese frosting for this (or use a can of frosting, I won’t tell). Kids and adults alike with love this frosting! It’s so pretty you can’t help but smile.

ingredients in rainbow frosting laid out on a marble counter.

Ingredients Needed

Vanilla Buttercream Frosting: For the best flavor, use my homemade recipe, or three cans of store-bought white or vanilla frosting.
Food Coloring: Gel coloring is the best for getting bright and vibrant colors. I usually use americolor gel food coloring but Wilton works too.
Cupcakes, Cookies, or Cake: Use your favorite vanilla cupcakes, chocolate cupcakes or anything you want to decorate with the frosting. Use colorful cupcake liners for even more rainbow fun!

I used the colors of the rainbow for this recipe. If you can’t find all of these colors, you can follow the instructions on the box and mix the ones you have to create the colors you want.

How to Make Rainbow Swirl Frosting

You’ll want to make your frosting by mixing softened unsalted butter with powdered sugar, then adding the vanilla extract and heavy cream (or milk). You can make your frosting with a hand mixer or stand mixer. You want a regular frosting consistency – if you’re using gel coloring it won’t thin it like water-based coloring does.
Divide the frosting into six bowls and tint each a different color. Stir well, so the colors are even.
I place my colors in piping bags or sandwich bags and pipe each color in the order of the rainbow onto a large piece of plastic wrap.
Form the frosting into a log by rolling up the plastic wrap and twisting the ends. Cut off one end of the plastic wrap.
Fit a piping bag with a tip (I use a Wilton 1M piping tip which is a star tip). Place the frosting log in the bag, and then pipe the swirl frosting onto your cupcakes or cake. If you want, decorate with rainbow sprinkles or decorations!

Expert Tips

I’ve already mentioned it, but it’s worth mentioning again: use GEL food coloring for the best results. Generic grocery store food coloring will not produce the same vibrant colors.
When you’re tinting your frosting, it’s always good to start with less and then add more to get your desired color.
This rainbow frosting is freezer-friendly! Once you’ve rolled it up in the plastic wrap and twisted the ends, place it in a freezer bag or airtight container, and it will keep for two months. Thaw it in the refrigerator before using it.

FAQs

How to store rainbow frosting?

Once you’ve frosted your cake or cupcakes, keep them loosely covered, and they will keep at room temperature for two days or in the refrigerator for four days.