These Funfetti Rainbow Cupcakes are bright inside and out. Homemade funfetti cupcakes stay moist and are studded with colorful sprinkles, then finished with a rainbow buttercream and mini marshmallow clouds. They’re perfect for birthdays, spring gatherings, or a festive St. Patrick’s Day treat.
Rainbow Cupcakes are cheerful and colorful—ideal for spring and summer parties or a whimsical unicorn birthday. The bright colors work well for any celebration; add a pot of gold and they’re great for St. Patrick’s Day.
Cooking Rainbow Cupcakes
There are several ways to make multi-colored cupcakes. You can tint and layer the batter like a full rainbow, or make a funfetti batter and add color in the frosting. For this version, the cake is a homemade funfetti batter with sequin or regular rainbow sprinkles mixed in for pops of color throughout.
Rainbow Frosting
In addition to confetti sprinkles inside the cupcakes, the rainbow effect comes from swirled buttercream on top. Instead of tinting one large batch of frosting and piling it high, these cupcakes get a curved rainbow piped across the top with mini marshmallow clouds for a playful finish.
Begin by piping a flat base of plain white frosting onto each cupcake using a Wilton 2A tip or similar flat piping tip. This creates a smooth surface for the rainbow arch.
To make the rainbow, divide a portion of the frosting into six small bowls and tint each with gel food coloring: red, orange, yellow, green, blue, and purple. Gel colors give stronger hues without thinning the frosting.
On a piece of plastic wrap, layer the colored frosting in rainbow order—red through purple. You can pipe each color as a straight line from small zip-top bags with the corner snipped, or spread them with a small spatula. Fold the plastic wrap over so the colors stack, then gently roll into a log and twist the ends to seal.
Trim one end of the wrapped log just next to the frosting and fit it into a piping bag fitted with a large star tip such as Wilton 1M or 2D. This creates a multicolored ribbon of frosting that will reveal all the stripes as you pipe.
Piping the Rainbow
Pipe a rainbow arch across the top half of the cupcake, twisting the piping bag slowly as you squeeze to show all the colors in each strand. Add a cluster of mini marshmallows at one or both ends to mimic fluffy clouds.
Tip: Twisting while squeezing can take a little practice—try it on a plate first. Slow, steady pressure helps keep the colors distinct and the arch even.
The finished cupcakes are moist, colorful, and fun to eat. The confetti inside and the rainbow buttercream on top create a whimsical presentation that delights both kids and adults.
Funfetti Rainbow Cupcakes
Ingredients
Funfetti Cupcakes (Yield: about 14)
- 1 ¼ cups (150 g) all-purpose flour, (stir, spoon, & level)
- 1 tsp baking powder
- ½ tsp salt
- ½ cup (118 ml) oil, (canola/vegetable)
- 1 cup (200 g) granulated sugar
- 2 large/XL eggs, room temperature
- 1 tsp vanilla extract
- ½ cup (118 ml) buttermilk, (or milk with 1 tsp vinegar/lemon juice)
- ¼ cup (48 g) rainbow sprinkles/sequins
Basic Vanilla Frosting (Yield: about 3 cups)
- ½ cup (113 g) butter, (salted or unsalted) room temperature
- ½ cup (118 ml) coconut oil or shortening, room temperature
- 4 cups (480 g) powdered sugar
- 2 tsp vanilla extract
- 2 Tbsp milk
Extras:
- mini marshmallows
- red, orange, yellow, green, blue, and purple gel food coloring
Instructions
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CUPCAKES: Preheat oven to 350°F (375°F for high altitude). Line muffin tin(s) with liners.
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Whisk together flour, baking powder, and salt in a medium bowl; set aside.
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In a large bowl, whisk oil and sugar. Add eggs one at a time, mixing well after each addition. Stir in vanilla.
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Add half the dry ingredients and mix until just combined. Add the buttermilk and mix, then fold in the remaining dry ingredients and sprinkles until just combined—do not overmix.
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Scoop batter two-thirds full into the lined cups (about 14 cupcakes). Bake 15–20 minutes, until a toothpick comes out clean or with a few moist crumbs and the cake springs back to the touch.
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FROSTING: Beat butter and coconut oil (or shortening) until smooth. Add powdered sugar, vanilla, and milk and mix until combined. Add up to ½ Tbsp additional milk if needed for consistency.
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Divide 1/4 cup of frosting into six small bowls and tint each with red, orange, yellow, green, blue, and purple gel food coloring. Reserve the remaining white frosting for the base.
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Layer the colored frosting on plastic wrap in rainbow order. You can spread each color with a spatula or pipe lines from small bags. Fold the wrap, roll into a log, twist the ends, trim one end, and place the frosting log into a piping bag fitted with a Wilton 1M or 2D tip.
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Fit a separate bag with a Wilton 2A tip and pipe a flat white swirl as the frosting base on each cupcake.
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Pipe the rainbow arch across the top, twisting the bag slowly as you squeeze so the colors show. Add mini marshmallows for clouds.
Notes
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- Cupcake recipe adapted from Pretty Simple Sweet
- Decoration idea inspired by classic rainbow cupcake techniques