Rainbow Frosting Cupcakes

5 from 42 ratings

Rainbow Frosting Cupcakes

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

Prep Time20

Cook Time20

Additional Time30

Total Time1 10

Course: Cupcakes

Cuisine: American

Servings: 12

Calories: 736kcal

Author: Chelsey White

Ingredients

Funfetti Cupcakes

1 1/4 cups all-purpose flour 160g
1 cup granulated sugar 200g
1 1/2 tsp baking powder 6g
1/2 tsp fine salt 3g
1/2 cup water 120g
1/2 cup full-fat sour cream, room temperature 120g
1/4 cup vegetable or canola oil 56g
1 large egg, room temperature 56g
1 tsp vanilla extract or vanilla bean paste 4g
1/2 tsp almond extract - optional 2g
1/3 cup rainbow jimmies / long sprinkles 60g

Rainbow Buttercream Frosting

1 cup (2 sticks) unsalted butter, room temperature 226g
2 tsp vanilla extract or vanilla bean paste 8g
1/4 tsp fine salt 2g
3 1/2 cups powdered sugar 454g or a 1 lb. box
2 Tbsp heavy cream or milk, room temperature 30g
Red, orange, yellow, green, blue, and electric purple gel food coloring

Recommended Equipment

Instructions

Funfetti Cupcakes

Begin by preheating the oven to 350°F/175°C. Place 12 cupcake liners in a muffin pan and set aside.
Add 1 1/4 cups all-purpose flour, 1 cup sugar, 1 1/2 tsp baking powder, and 1/2 tsp salt to a large bowl. Whisk together until combined.
Next, add 1/2 cup water, 1/2 cup sour cream, 1/4 cup vegetable oil, 1 egg, 1 tsp of vanilla extract, and 1/2 tsp of almond extract into the dry ingredients. Mix until the batter comes together and is smooth.
Gently fold in 1/3 cup of rainbow sprinkles with a rubber spatula.
Fill the cupcake liners about 3/4 of the way full. Bake 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.
Let the cupcakes cool for 10 minutes in the pan, then move them to a wire rack to finish cooling. If you want to accelerate the cooling process, pop the cupcake pan into your freezer for about 30 minutes.

Rainbow Buttercream Frosting

Beat 1 cup of butter, 2 tsp vanilla extract, and 1/4 tsp fine salt on a medium speed for 30 seconds with a paddle attachment or hand mixer until smooth.
Slowly mix in 3 1/2 cups of powdered sugar and 2 Tbsp of heavy cream on a low speed. Beat on low until the ingredients are fully incorporated.
If the frosting seems too thick, add in additional cream (1 Tablespoon at a time). If the frosting seems too thin, add more powdered sugar (quarter of a cup at a time). Or, if you aren't sure what consistency you're after, check out my buttercream consistency guide.
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. I placed each color of frosting in its own small piping bag to pipe neat lines, but I think this step can be bypassed to make the process simpler and create less waste.
Repeat step 5 to make orange, yellow, green, blue, and purple frosting and spread each one out in lines on the plastic wrap like in the photo above. 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.
Place the buttercream log cut end-first into a large piping bag fitted with an open star piping tip. Pipe large swirls onto the fully cooled cupcakes, then enjoy!

Video

Notes

Yield

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 to bake for 10-12 minutes.

Tips for Making These Rainbow Funfetti Cupcakes

Properly measure the flour (spoon it 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.
Ingredients at room temp mix together better, so be sure you set out any cold ingredients ahead of time.
Use gel or powder food coloring to easily create vibrant colored frosting without throwing off the consistency of the frosting.

Making These 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.

Nutrition