Hello gorgeous! Slice into this elegant white rainbow bundt cake and discover a bright rainbow hidden inside. My Rainbow Bundt Cake is cheerful both inside and out, and the best part is it’s simple to make with the tips, video, and recipe below. Let’s get started.
Rainbows 100 Ways
I love making rainbow-themed cakes. For more than ten years, holidays and special occasions have been the perfect reasons to try new cake designs and flavors. Each celebration gives me an excuse to bake something bright and playful.
St. Patrick’s Day is no exception. I’ve hidden rainbows in stacked cake layers, tucked them into buttercream, and decorated exteriors with rainbow accents. If you follow my work, you know I enjoy finding new ways to add vivid color to my cakes, inside and out.
All the rainbow things
From rainbow stripes and ruffles to rosettes, Russian piping tip flowers, petals, swirls, sand art with nonpareils, and cakes rolled in sprinkles — the rainbow theme shows up in many forms. I’m always experimenting with colorful techniques to make every cake feel joyful and playful.
Turning it into a bundt
Adding a hidden rainbow to a bundt cake felt inevitable. With St. Patrick’s Day approaching, I finally tested placing a rainbow design inside a circle bundt pan. The circular shape lets the rainbow arch reveal itself in slice after slice, similar to zebra or marble designs but with vibrant color.
Inspiration
After years of baking, new cake ideas come quickly. I keep a notebook with me to capture design and flavor ideas the moment they arrive. This rainbow-in-a-bundt idea came naturally — I’ve made bundts with surprises before and imagined how a rainbow curve would look inside a donut-shaped pan. Planning the execution was straightforward because I’m used to thinking in reverse for surprise-inside cakes.
Credit
I had a few new bundt pans I received for Christmas and saved this idea for the occasion. After creating, photographing, and filming my version, I later learned others had explored similar techniques. That’s common in baking—many ideas evolve and are reinvented over time.
Where have we seen it?
Bakers have created rainbow-inside bundts for years, with beautiful variations online going back a decade or more. Rather than claim sole credit, I want to celebrate the many bakers who inspired this playful concept.
An invitation to you
I won’t list these earlier versions as my idea credit since I created my cake without prior knowledge of them, but I encourage you to explore different recipes and tutorials and choose the approach that fits your baking style.
If you enjoy variations, look around for other versions and pick the one that works best for your skill level and taste.
All that said, I’m excited to add my Rainbow Bundt Cake to the mix and hope it inspires you to try something new in your kitchen. This is my take on a colorful, hidden-rainbow bundt — have fun with it!
How to make the rainbow bundt cake design
The design is built by layering colored batter into the center of a circle bundt pan. Below are clear steps, and if you prefer visuals, a video is provided to show the full process.
Key tips: pipe each color carefully into the center ring without touching the outer sides, tap the pan to level the batter between layers, and if you want the traditional rainbow order, pipe red first so it ends up on the outside top of the slice. Watch the video for a quick visual guide.
What you’ll need
These tools make the process easier and help produce even, clean color layers.
Circle bundt pan
Use a circle bundt pan (donut-shaped) so the rainbow arch reads clearly in each slice. Using other bundt shapes can obscure the classic half-circle rainbow effect.
Piping bags
Have seven piping bags on hand for the colored batter and white batter. Fill them before snipping the tips for controlled piping.
Gel colors
Gel food coloring provides vibrant, concentrated hues that won’t add extra liquid to the batter. A little goes a long way.
Bowls and spoons
Separate bowls help portion batter evenly and keep colors tidy. Paper bowls work if you prefer fewer dishes.
For the finish, I use a bright white chocolate drip and scatter rainbow jimmies or sprinkles on top. Choosing bright white candy melts keeps the drip from looking ivory so the colors pop against it.
Below is a video showing the full process.
That’s it — I can’t wait to see your rainbow bundt cakes this St. Patrick’s Day and beyond. Happy baking!
xo,
Mandy
Get the Recipe:
Rainbow Bundt Cake
Pin Recipe
Leave a Review
Ingredients
White / Rainbow Bundt Cake
- 3/4 cup buttermilk , room temperature
- 2/3 cup sour cream , room temperature
- 4 egg whites , room temperature
- 1/3 cup vegetable oil
- 1 Tablespoon vanilla
- 1 15.25oz Box cake white mix, I used Duncan Hines for the best taste and texture, but other brands will work.
- rainbow gel colors (red, orange, yellow, green, blue, purple)
White Chocolate Ganache Drip
- 1 cup bright white chocolate candy melts , Wilton or another bright white brand
- 1/4 cup heavy cream
Extras
- 1/2 cup rainbow jimmies/sprinkles
Equipment
-
1 circle bundt pan
-
piping bags
-
bowls & spoons
Instructions
For the rainbow bundt cake:
-
Preheat oven to 325°F (163°C). Grease the round bundt pan with shortening and dust with flour. Set aside.
-
In a large bowl, whisk together the wet ingredients (buttermilk, sour cream, egg whites, oil, vanilla) except the cake mix and gel colors. Sift in the white cake mix and gently stir until just combined.
-
Portion batter into six small bowls, about 1/2 cup each. Add a small amount of gel color to each bowl (red, orange, yellow, green, blue, purple) and stir to combine. Fill six piping bags with the colored batter.
-
Spread a thin layer of plain white batter in the bottom of the circle bundt pan. Snip a small round opening in each piping bag tip (about marble-sized).
-
Pipe the first colored ring into the center, avoiding the outer edge of the white layer. Tap the pan gently to level, then pipe the next color in a concentric ring. Continue with remaining colors, tapping between each to settle the batter.
-
Pipe a small white ring in the center, tap to level, then pipe the remaining white batter evenly over the top.
-
Bake for 25–27 minutes or until the center is set. Remove from oven, let cool in the pan 30 seconds, then invert onto a wire rack to cool completely.
For the White Chocolate Ganache Drip
-
In a microwave-safe bowl, stir together white chocolate candy melts and heavy cream. Heat 1 minute, stir until smooth. If needed, microwave an additional 15 seconds and stir. Transfer to a drip bottle or spoon, cool slightly, then apply drip to the cake and immediately add sprinkles.
-
Slice to reveal the hidden rainbow and enjoy.
Video
Originally published summer 2022, republished 2/15/2023