Chocolate Cupcakes with Rainbow Buttercream Frosting

By Rachel // March 4, 2020 // 7 comments // Share

Moist homemade chocolate cupcakes with fluffy rainbow buttercream frosting. A fun and festive treat for St. Patrick’s Day celebrations or any day of the year!

It’s been longer that intended since I shared something new, but that definitely doesn’t mean I haven’t been thinking up crazy delicious ideas to share! There’s been plenty of thinking, planning and writing recipes, but real life struck and food had to wait. Three weeks of back to back illnesses between two kids and winter school vacation. I’m glad that’s over and everyone is on the mend! And thankfully just in time for delicious holiday treats to be made! One of my favorites in fact… mostly because it is incredibly close to my birthday so I sort of throw them together into a big celebration.

Super cheesy thought but why aren’t there fun St. Patrick’s Day movies? There seem to be movies that fit for just about every other holiday during the year, so why not that? I’m always game for fun, cute, cheesy holiday and seasonal themed movies…more so the past few years. I did a quick search and mostly turned up creepy horror movies. Definitely not my cup of tea by any means. Of course, if you search for movies based in Ireland, more options come up. Still not quite what I was hoping for…definitely not holiday themed but it may have to do the trick. I just might have to make PS I Love You my new yearly St. Patrick’s Day movie. Bonus, I haven’t watched it in years!

Most of my St. Patrick’s Day sweets tend to be on the boozier side. Standard holiday food this time of year. Guinness and Baileys are pretty much a guaranteed crowd pleaser, unless you’re a child or don’t eat or drink anything that even has alcohol in it.

In walk these cupcakes… okay, not literally because that would be weird. But seriously…

Super fun and festive cupcakes, perfect for a St. Patrick’s Day celebration (or a birthday…really any celebration or just because)! Moist homemade chocolate cupcakes topped off with fluffy rainbow swirled buttercream frosting! So bright and colorful, they’ll put a smile on anyone’s face! A perfect holiday treat!

They’re fun to look at and eat! Hands down one of my favorite frostings to make, to date. Be sure to add these festive rainbow frosted cupcakes to your baking plans asap!

Tips tricks and questions answered…

Can I make this into a cake instead?
This should work well as an 8 or 9-inch cake. You’ll want to check your bake time, as it may vary from the cupcake bake time listed below. If making into a cake, frosting can be reduced in half. Piping rosettes with a 1M piping tip or other star tip would work well.

Can I make cream cheese frosting instead?
Absolutely! Follow the directions for this recipe. You may want to increase it to at least 1 and 1/2 batches to have extra frosting.

Can I use dark brown sugar instead of light brown?
Yes! It will give a bolder flavor, but should work just fine as a 1:1 swap.

Can I use dark cocoa powder?
Yes! Substitute 1:1 with the amount already listed for standard unsweetened cocoa powder.

Can I make substitutions to the ingredients?
Yes and no. Baking is a science. This recipe works with the exact measurements listed. Altering one or several of those can cause the recipe to fail. If you’re familiar with baking substitutions, go for it! Outside of any alterations I’ve already mentioned, for specific substitution questions, ask in the comments below.

How many will this serve?
This recipe will serve 10, as it makes 10 standard sized cupcakes.

How should this be stored?
Store at room temperature for up to several days in an airtight container. It may also be stored in the refrigerator and eaten chilled or brought to room temperature prior to serving.

What piping tip did you use?
A jumbo closed star piping tip was used for this recipe.

What food color did you use?
Americolor gel food color was used for this recipe. You can use another brand if you have it on hand, the names and shades will vary, but be sure to use gel color only.

Can I use liquid food color for the frosting?
No. Gel food color is recommended as it is both highly concentrated in color and will not alter the consistency of the frosting. A little color goes a long way.

Print Recipe

Chocolate Cupcakes with Rainbow Buttercream Frosting

Moist homemade chocolate cupcakes with fluffy rainbow buttercream frosting. A fun and festive treat for St. Patrick's Day celebrations or any day of the year!

Prep Time10 mins

Cook Time20 mins

Total Time2 hrs

Course: Dessert

Cuisine: American

Keyword: Chocolate, Cupcake

Servings: 10

Ingredients

Cupcakes

• 1/4 C unsalted butter softened
• 1/4 C granulated sugar
• 1/4 C light brown sugar
• 1 large egg
• 1 tsp vanilla extract
• 1/4 tsp salt
• 1/2 tsp baking soda
• 6 Tbsp unsweetened cocoa powder
• 1/3 C sour cream
• 1/2 C milk
• 1 C all purpose flour

Frosting

• 1 1/2 C unsalted butter
• 1 1/2 tsp vanilla extract
• 4 1/2 C powdered sugar
• 4 1/2 Tbsp heavy cream
• Americolor gel colors see note

Instructions

• Preheat oven to 350°F. Line a standard cupcake pan with 10 paper liners.
• In a large bowl or stand mixer, cream together butter and sugars until light and fluffy. Mix in egg and vanilla, followed by salt, baking soda and cocoa powder. Scrape bowl as needed. Mix in sour cream, combining well before alternating additions of milk and flour. Mix until just combined and no streaks remain.
• Divide batter equally between prepared liners using a large cookie scoop. Liners should be roughly 2/3 full.
• Bake at 350°F for 18-20 minutes or until a toothpick inserted comes out clean or with a few moist crumbs. Cool in pan for several minutes or until easy to handle. Transfer to a wire rack to cool completely.
• When cupcakes have cooled completely, prepare frosting. In a large bowl or stand mixer, beat butter until light and fluffy. Add vanilla, followed by one cup of powdered sugar at a time. Scrape bowl as needed. Slowly add 1 tablespoon of heavy cream at a time until fully incorporated and desired consistency is reached.
• Divide frosting equally between six clean bowls. Tint with desired gel food colors. Transfer each color to their own small piping bag with the tip snipped off or into a quart size plastic bag with a corner cut off. Lay a single sheet of plastic wrap on flat work surface. Piping one color at a time, pipe a 1-inch thick stripe of frosting. Repeat process immediately next to the first color with next color. Repeat with remaining colors until a rainbow has been piped. Carefully pull up on plastic wrap to roll frosting over onto each other, creating a large log of frosting. Overlap plastic wrap and twist ends to seal. *This may be done in two batches of stripes/frosting logs.
• Prepare a large piping bag with desired piping tip. Cut off one twisted end of plastic wrap from prepared frosting log. Insert wrapped frosting into prepared piping bag. Frost cupcakes as desired.
• Enjoy immediately. If making ahead, cupcakes can be stored at room temperature or chilled in the refrigerator for up to several days. Chilling will cause the cupcakes and frosting to firm up. For a softer consistency, bring to room temperature prior to eating.

Notes

Recipe yields 10 standard cupcakes.

A jumbo closed star piping tip was used for this recipe.

If decorating with a single layer of frosting, frosting amounts may be reduced. As written, there will be a small amount of frosting leftover.

Americolor gel colors used: super red, orange, lemon yellow, leaf green, electric blue and regal purple.

An original recipe from Baked by Rachel

More sweet treats for St. Patrick’s Day:

• Guinness chocolate cupcakes with Baileys brown sugar cream cheese frosting
• Guinness chocolate layer cake with brown sugar cinnamon cream cheese frosting
• Mint chocolate cheesecake bars
• Baileys chocolate pudding with Baileys whipped cream
• Mini Baileys chocolate cheesecakes with Baileys whipped cream
• Guinness chocolate cupcakes with cinnamon cream cheese frosting

Items used in this recipe:

This post contains affiliate links.

Share this: