These rainbow frosting cupcakes are so stunning! They’re made with tender funfetti cupcakes and are frosted with homemade buttercream frosting.

While it does take a bit of time to color the frosting, the result is totally worth it.

How to Make These Rainbow Frosting Cupcakes

Let’s walk through each step of this recipe to make sure it turns out as amazing as possible! I’ve also shared a video tutorial below.

Step 1: Make the Funfetti Cupcake Batter

First, we tackle the funfetti cupcakes! Preheat the oven to 350°F/175°C and line a muffin pan with 12 cupcake liners.

Following the recipe card at the bottom of this post, combine the dry ingredients and then mix in the wet ingredients. Then it’s time to fold in the rainbow sprinkles.

Step 2: Bake the Cupcakes

Fill the cupcake liners 3/4 full and bake them for 19-22 minutes, or until a toothpick comes out with a few moist crumbs. Rotate the pan halfway through to help the cupcakes bake evenly.

Remove the pan from the oven. Let the cupcakes cool in the pan for 10 minutes, then remove them and place them on a wire rack to finish cooling.

If you’re in a rush, place the entire pan in the freezer for 30 minutes to accelerate the cooling process.

Step 3: Make the Vanilla Buttercream

While the cupcakes bake and cool, make the vanilla frosting.

If the frosting seems too thick, add an extra Tbsp of heavy cream. If it seems too thin, add in another 1/4 cup of powdered sugar.

Or if you’re unsure what consistency the frosting should be, check out my frosting consistency guide

Step 4: Color the Rainbow Buttercream

At this point, you should have about 3 cups of frosting. Lay out a piece of plastic wrap that is about 1 foot long.

Scoop 1/2 cup of frosting into a separate bowl and color it red with a generous squirt of gel food coloring. Spread the red frosting in a thin, long line on the plastic wrap.

Repeat the step above to make the orange, yellow, green, blue, and purple frosting, and spread each color out in lines on the plastic wrap like in the photo below.

All 6 colors can be made in the same bowl. The remnants from the prior color will help give the color palette a cohesive look.

Carefully roll the plastic wrap to make a frosting log. Make sure you roll the plastic wrap in the same direction that the frosting lines are spread.

Twist the plastic wrap at the ends of the frosting log, then cut off one of them.

Step 5: Frost the Cupcakes

Place the buttercream log cut end first into a large piping bag fit with an open star piping tip.

Pipe large swirls onto the fully cooled cupcakes, then enjoy!

If you don’t have any frosting bags and tips, you can also use a freezer Ziplock bag and trim the corner to have a 1-inch opening.

Substitutions and Swaps – Funfetti Cupcakes

This recipe uses quite a few ingredients and I know you might not have them all on hand. Or if you have food allergies or restrictions, I’ve got you covered.

Below are some swaps and substitutions that you can make.

• All-Purpose Flour – This recipe turns out best with AP flour, but you can use a gluten-free flour blend or cake flour if needed.
• Granulated Sugar – I do not recommend reducing the amount of sugar or changing the type of sugar, as it will change the texture of these cupcakes.
• Vegetable Oil– You can also use any flavorless oil or melted butter if needed.
• Sour Cream – Full-fat yogurt, buttermilk, or an alternative yogurt or milk (almond, soy, oat) can also be used.
• 1 Large Egg – If you have an egg allergy, you can try using a flaxseed egg or a vegan egg replacer like this made by Bob’s Red Mill.
• Vanilla Extract – Vanilla extract helps enhance the flavor in these cupcakes, but you can use any extract you want like lemon or coconut, or omit it altogether.
• Almond Extract – I love adding a splash of almond extract too, but this ingredient is optional. It can be skipped, or you can add additional vanilla in its place.

Substitutions and Swaps – Rainbow Buttercream Frosting

• Unsalted Butter – If you only have salted butter on hand, you can use it in place of the unsalted butter. Just be sure to omit the salt that this frosting recipe calls for. You can also use vegan butter in its place (just be sure to omit the salt!).
• Heavy Cream – Whipping cream, coconut cream or alternative milk (soy, almond, oat, coconut) will work fine in this frosting recipe if that’s what you have on hand.
• Gel Food Coloring – I highly recommend using gel or powdered food coloring to make vibrant-colored frosting without throwing off the consistency of the frosting. Liquid food coloring can be used if you’re really in a pinch, but I don’t recommend it.

How to Make Vibrant Rainbow Frosting: The Microwave Method

If you’re using gel or powder food coloring and your buttercream STILL doesn’t look as vibrant as you want, don’t worry.

I have a quick fix that is guaranteed to leave you with vibrant buttercream. I like to call it the microwave method!

Scoop 1 Tablespoon of the colored buttercream into a small microwavable bowl. Add additional gel food coloring and mix until the frosting reaches the desired color.

Then microwave the frosting for 5-10 seconds. The frosting should be runny but deeper in color. Mix this back into the bowl of frosting and you should achieve a vibrant color.

I like this method because it always works and is a quick way to make deeply colored frosting. The only thing I don’t like about it is that it changes the consistency of the frosting.

If you end up using this method, let the frosting sit for about 30 minutes before you pipe with it to let it thicken back up.

How Many Cupcakes Does This Recipe Make?

This recipe makes 1 dozen cupcakes. It can be halved (scramble an egg and use half the mixture, or just use an egg white) or doubled to change the yield as needed.

This recipe can also be used to make mini rainbow frosting cupcakes! This recipe makes about 40 mini cupcakes, which only need 10-12 minutes to bake.

Making These Rainbow Frosting Cupcakes in Advance & Storage Tips

You can make these cupcakes in advance. If stored unfrosted in an airtight container, they can sit out overnight at room temperature or be stored for up to a week in the fridge.

These cupcakes can also last up to 3 months in the freezer. Wait to frost them until they’re thawed if you plan to freeze them.

Make the frosting ahead of time too or save any leftover frosting! It can be stored in an airtight container in the fridge for up to a month or in the freezer for up to 3 months.

I recommend storing it in a piping bag. When you’re ready to use it again, let the bag sit out for a few hours or overnight at room temperature until it’s fully thawed.

Frosted cupcakes can sit at room temperature for a couple of days or be stored in the fridge in an airtight container for up to 5 days.

Tips for Making These Rainbow Funfetti Cupcakes

• Ingredients at room temp mix together better. Set out any cold ingredients ahead of time.
• Properly measure the flour (spoon into the cup measure then level) or use a kitchen scale to measure your dry ingredients.
• Use a cookie scoop to easily fill your cupcake liners.
• Use gel or powdered food coloring to easily create vibrant colored frosting without throwing off the consistency of the frosting.
• If you’re struggling to get your frosting a deep enough color, follow my microwave tip in the section above.
• I find the sprinkles that work best are rainbow jimmies. They are the longer sprinkles that you used to (and may still) put on your ice cream. These sprinkles keep their color, and won’t bleed into your batter.

Let Me Know What You Think!

If you make these rainbow frosting cupcakes, I’d love to hear what you think! Please leave a rating and comment below.

Don’t forget to tag me @chelsweets and use #chelsweets so that I can see your amazing creations on social media.

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