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This Rainbow Jello Cake is pure magic, soft vanilla cake stacked with fluffy jello whipped cream frosting in four dreamy colors, all hidden inside a snowy white shell. I made the first one for Lizzie’s rainbow birthday party and the gasp when we cut into it was everything. It is a showstopper with the same fun, colorful spirit as our frosted Lofthouse cookies.
Built on a boxed cake mix and a few packets of jello, this rainbow jello cake looks fancy but is surprisingly simple to put together.
Rainbow Jello Cake Quick Look
- 🕒 Prep Time: 30 minutes
- 🌡️ Cook Time: 25 minutes
- ⏳ Total Time: 2 hours 30 minutes
- 🍽️ Serving: 12 servings
- ⚡ Calories: 366kcal
- 🌶️ Flavor Profile: Soft vanilla cake layered with fluffy, fruity jello whipped cream in rainbow colors
- ✋ Difficulty: Easy, on par with our spice layer cake
Quick Answer
Bake a white cake in two rounds and cool, then whisk each box of jello with boiling water and fold in whipped topping to make four colors of fluffy frosting. Split the cakes into layers, stack them with a different jello frosting between each, then smooth the rest over the outside. Chill to set and slice into a bright Rainbow Jello Cake.
Jump to:
Why This Recipe Works
Click to see the technique science
- Boxed cake mix keeps it easy. Starting with a white cake mix means a reliable, tender crumb with zero fuss, so you can focus on the colorful layers.
- Jello makes the frosting. Dissolved jello whisked into whipped topping creates a fluffy, fruity frosting that doubles as the filling and the color.
- Four layers, four colors. Splitting two cakes into four thin layers gives you a tall, dramatic rainbow reveal with every slice.
- Chilling sets the frosting. A rest in the fridge firms up the whipped jello so the cake slices cleanly and the layers stay distinct.
- White shell, hidden surprise. Coating the outside in plain whipped topping keeps the rainbow a secret until you cut in.
- Make ahead friendly. The whole cake holds beautifully in the fridge, so you can build it the day before a party.
Why You’ll Love This Recipe
- A jaw dropping party centerpiece with a hidden rainbow that makes kids and adults light up when you slice it.
- It starts with a cake mix and a few pantry boxes of jello, so it is way easier than it looks. For another fun cake, try our spice layer cake.
- Totally customizable colors, pick any four jello flavors to match a birthday theme, holiday, or favorite color combo.
Key Ingredients
Just a few simple grocery items turn into this colorful showstopper. Here is what each one does.
- White cake mix: The shortcut base for a soft, neutral cake that lets the rainbow layers shine. Bake it per the box with oil, eggs, and water.
- Jello: Four flavors do double duty as the color and the fruity flavor in the whipped frosting. Pick any colors you love.
- Whipped topping: Folded into the dissolved jello, it makes a light, fluffy frosting and the smooth white outer shell.
- Boiling water: Dissolves the jello completely so the frosting is silky, not grainy.
- Cake mix add ins: Oil, eggs, and water are all you need to turn the box into two tender cake rounds.
See recipe card for exact quantities.
Variations and Substitutions
This cake is endlessly customizable. Here are a few ideas.
- Theme the colors: Use red, white, and blue for the Fourth of July or pastels for Easter.
- Pick the flavors: Any jello flavors work, so match them to your favorite fruits.
- Add sprinkles: Press rainbow sprinkles onto the outside for even more color.
- Make cupcakes: Bake the mix as cupcakes, like our angel food cupcakes, and swirl on the jello frosting.
- Two layers: Skip splitting the cakes for a quicker two color version.
How to Make Rainbow Jello Cake
- Bake the white cake in two 8 inch rounds according to the box directions, then cool the layers completely.
- Working one color at a time, whisk each box of jello with half a cup of boiling water until dissolved, then let it cool for 10 minutes.
- Whisk a cup and a half of whipped topping into each jello, chill for 2 hours, then whip until smooth and add more whipped topping until fluffy.
- Split each cake into two thin layers. Place the first layer on a platter and spread on your first jello color.
- Stack the remaining layers, frosting each one with a new jello color, until all four colors are layered up.
- Dollop and smooth the remaining frosting over the outside for an ombre look. Chill for at least an hour to set, then slice and serve.
Recipe Tips & Tricks
- Cool the cakes completely before frosting, or the whipped jello will slide and melt.
- Let the jello cool for 10 minutes before adding whipped topping so it does not deflate.
- Do not skip the 2 hour chill on the frosting, it firms up so it whips into a fluffy, spreadable consistency.
- Reserve a little of each color in case you want to touch up the outside or add dollops.
- Use a serrated knife to split the cake layers evenly for the cleanest rainbow.
- Chill before slicing so the layers stay distinct and the cake cuts neatly.
- Build it ahead. This cake actually slices best after a night in the fridge.
Serving Ideas and Suggestions
This cake is made for a party. Serve generous slices at a birthday or rainbow themed bash and watch everyone marvel at the hidden colors. It pairs beautifully with our lemon lime angel food cupcakes on a colorful dessert table.
Keep the rainbow theme going with other bright treats. Set out a plate of frosted Lofthouse cookies and our pretty queen cakes for a spread that is as fun to look at as it is to eat.
Leftovers keep well chilled, so cover and refrigerate any extra slices. For another layered showstopper, our lemon blueberry trifle brings the same wow factor with zero baking.
Rainbow Jello Cake FAQs
Any flavors work since the color is the main goal. Pick four that give you bright, distinct colors like strawberry, lime, lemon, and berry blue. Match them to a party theme if you like.
Yes, and it is actually better made ahead. Build the cake a day before, keep it covered in the fridge, and it will slice cleanly with distinct, set layers.
Because the frosting is whipped topping based, keep the cake refrigerated and covered. It stays fresh for up to three days. Do not leave it at room temperature for long.
The jello mixture needs the full 2 hour chill before whipping so it firms up. If it is still soft, refrigerate longer before whisking in more whipped topping.
It is best enjoyed fresh from the fridge. Freezing can make the whipped jello frosting weep and lose its fluffy texture once thawed, so chilling is the better choice.
Splitting two cakes into four layers gives the tallest, most dramatic rainbow. For a quicker version, leave them whole for a two color cake instead.
Love a fun, colorful bake? Make our soft frosted Lofthouse cookies next for another bright, crowd pleasing treat.
Rainbow Jello Cake
Ingredients
- 1 box white cake mix plus ingredients to make the cake
Jello Frosting
- 4 – 3 ounce boxes jello, any flavors
- 2 Cups boiling water
- 32 ounces whipped topping
Instructions
- Bake the cakes in 2 8-inch round baking pans according to the box directions.1 box white cake mix
- Allow the cakes to cool in the pan for 10 minutes. Invert them onto a wire rack and cool completely.
- While the cake is cooling make the frosting, working with one color at a time. Add the first packet of jello to a large bowl with 1/2 cup of boiling water and whisk until dissolved. Repeat with the other 3 colors.4 – 3 ounce boxes jello, any flavors, 2 Cups boiling water
- Allow the mixtures to sit for 10 minutes to cool.
- Whisk 1 1/2 Cups of the whipped topping into each bowl. Cover and refrigerate for 2 hours.32 ounces whipped topping
- With an electric hand mixer, whip the mixture until it breaks up.
- Add 1 1/2 cups more whipped topping and whip until smooth. There will still be a few lumps, but that’s okay. Repeat with the other colors.
- To assemble, cut each layer of cake into two. Place the bottom of one layer onto your serving platter.
- Reserve about 1/4-1/3 cup of your first jello frosting and spread the rest onto the cake layer.
- And the other half of the cake layer on top. Repeat the frosting step with your next Jello color.
- Add the next layer, top side down. Frost with your 3rd color.
- Finally, add the last layer of cake on top, bottom side up. Add the remaining color of frosting.
- To create the frosted ombre effect on the outside of the cake, you will dollop the remaining frosting over it.
- Take a bench scrapper or offset spatula and evenly smooth out the frosting around the outside of the cake.
- Place in the fridge for at least one hour to set, and serve.
Notes
- Let the Cake Cool Completely: Ensure your cake is room temperature before the Jello mixture goes on.
- Even Frosting Layers: Keep those layers smooth for the most visually appealing slice.
- Chill to Perfection: A few hours in the fridge makes slicing a breeze.
- Mix and Match Flavors: Be bold with your Jello choices for a truly unique cake.
- Garnish Galore: Top your cake with fresh strawberries, fresh berries, or even a sprinkle of your favorite toppings for that extra special touch.
Nutrition
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Oh my goodness gracious, this looks divine!!!! I especially your food-tography 🙂 totally pinning, have a great day! xo
Never heard of Jello frosting before! I bet my kids would love it!
This looks soo pretty!
This looks so good! I love jello frosting and the pretty rainbow colors are gorgeous!
I have never seen a cake like this. It is such a beautiful cake, and it looks like a perfect spring dessert. I am interested in trying this.
How pretty! It’s perfect for Spring! -Marci @ Stone Cottage Adventures