Easy Super Moist Rainbow Cake Recipe

You know those cakes that make everyone smile the second they walk in the door? This easy super moist rainbow cake does exactly that. Soft, tender layers bake up in bright colors, then stack with creamy frosting for a party-ready dessert that tastes as good as it looks. No fancy tools, no pastry degree—just a few bowls, food coloring, and a little patience while it cools.

I’ll walk you through every step so you get vibrant colors, even layers, and a fluffy crumb every time. We’ll cover tips to keep the batter moist, how to divide the colors cleanly, and the simple frosting that ties it all together. Grab your mixing bowls—this cake brings the magic.

Why This Rainbow Cake Turns Out Moist and Vibrant

This cake uses a few baking tricks to lock in moisture and keep the crumb soft and tender.

• Oil and butter combo: Butter adds flavor, oil adds moisture that stays even after chilling.
• Buttermilk for tenderness: A little acidity softens gluten so each bite feels light.
• Whole eggs plus an extra white: Structure from yolks, lift from whites for a fluffy texture.
• Proper batter mixing: Creamed butter-sugar for air, then gentle mixing to avoid toughness.
• Gel food coloring: Intense color without thinning the batter.
• Low-and-steady baking: Even rise and flat tops with minimal doming.

Ingredients

For the Rainbow Cake Layers

• 2 3/4 cups (345 g) cake flour (for a fine, soft crumb; sub AP flour minus 2 tbsp and add 2 tbsp cornstarch if needed)
• 1 1/2 cups (300 g) granulated sugar
• 2 tsp baking powder
• 1/2 tsp baking soda
• 1/2 tsp fine sea salt
• 1/2 cup (113 g) unsalted butter, room temp
• 1/3 cup (70 g) neutral oil (canola or vegetable)
• 3 large eggs + 1 egg white, room temp
• 1 cup (240 ml) buttermilk, room temp
• 2 tsp pure vanilla extract
• Gel food coloring in red, orange, yellow, green, blue, and purple

For the Vanilla Frosting

• 1 cup (226 g) unsalted butter, room temp
• 4 cups (480 g) powdered sugar, sifted
• 3–4 tbsp heavy cream (or milk, adjust for spreadable consistency)
• 2 tsp pure vanilla extract
• Pinch of salt

Optional Decorations

• Rainbow sprinkles
• White chocolate shavings
• Edible glitter

How to Make This Super Moist Rainbow Cake

Set Up for Success

• Prep pans: Grease and line three 8-inch round pans with parchment circles. Lightly flour the sides.
• Preheat: Set oven to 335°F (170°C) for even baking and flat tops.
• Room temp ingredients: Butter, eggs, and buttermilk should feel slightly cool but pliable.

Make the Batter

1. In a large bowl, whisk flour, baking powder, baking soda, and salt.
2. In a stand mixer, beat butter and sugar on medium-high for 3 minutes until pale and fluffy.
3. Beat in oil until glossy, about 30 seconds.
4. Add eggs and egg white one at a time, mixing just to combine. Scrape bowl.
5. Stir vanilla into the buttermilk.
6. Add dry ingredients in three parts, alternating with buttermilk, starting and ending with dry. Mix on low until just smooth. Do not overmix.

Color the Batter

• Weigh the batter or eyeball it into six equal portions in separate bowls.
• Tint each bowl with gel color: red, orange, yellow, green, blue, purple. Start with a little color, then build to intensity.
• Stir gently to avoid knocking out air.

Bake the Layers

You have two options depending on pans and oven space.

• Three-pan method: Bake three colors at a time. Spread each color into a thin even layer. Bake 12–15 minutes until the center springs back. Cool 10 minutes in pans, then turn out to cool completely.
• Single-pan method: If you have one pan, bake layers one at a time, re-lining the pan each time. Keep colored batters covered so they don’t dry out.

Repeat until you bake all six colors. Trim any domes with a serrated knife once cool.

Make the Frosting

1. Beat butter on medium-high for 2 minutes until creamy.
2. Add powdered sugar, salt, and vanilla. Mix on low until combined.
3. Add cream a tablespoon at a time until the frosting looks smooth and spreadable. Whip on medium-high for 1–2 minutes for fluff.

Assemble the Cake

1. Place the purple layer on a board. Add a thin layer of frosting.
2. Stack blue, green, yellow, orange, then red, frosting lightly between each. Use about 1/3 cup frosting per layer to avoid slipping.
3. Chill the stacked cake for 15 minutes to set.
4. Apply a thin crumb coat. Chill 15 minutes, then finish with a smooth final coat.
5. Decorate with sprinkles, swirls, or keep it sleek and white.

How to Store Your Rainbow Cake

• At room temp: Keep covered for up to 2 days if your kitchen stays cool.
• Refrigerate: Store well-covered for 5 days. Bring slices to room temp before serving for the best texture.
• Freeze layers: Wrap unfrosted layers in plastic and foil. Freeze up to 2 months. Thaw wrapped at room temp, then frost.
• Freeze assembled cake: Chill until firm, wrap, and freeze up to 1 month. Unwrap and thaw in the fridge overnight.

Benefits of Making This Rainbow Cake

• Showstopper visuals: Six bright layers that slice beautifully.
• Moist crumb that lasts: Oil and buttermilk keep the cake tender for days.
• Flexible timing: Bake layers ahead and assemble later.
• Beginner-friendly steps: Clear mixing method and forgiving batter.
• Customizable look: Smooth sides or sprinkle explosion—your call.

What to Avoid for Best Results

• Don’t overmix: Stop as soon as the flour disappears to prevent a tough crumb.
• Don’t use liquid food dye: It waters down batter and fades in the oven.
• Don’t skip parchment: Lined pans release clean layers you can stack easily.
• Don’t stack warm layers: Warm cakes slide and tear. Cool completely first.
• Don’t overload frosting between layers: Too much causes slipping and uneven slices.

Rainbow Cake Variations You Can Try

• Lemon-vanilla rainbow: Add 1 tbsp lemon zest to batter and 1 tbsp lemon juice to frosting.
• Funfetti rainbow: Fold 1/2 cup rainbow jimmies into each colored batter for speckled layers.
• Chocolate-frosted rainbow: Swap vanilla frosting for whipped chocolate buttercream.
• Gluten-free version: Use a 1:1 gluten-free baking blend and add 1 tbsp milk if batter feels thick.
• Mini rainbow cake: Bake in 6-inch pans for taller slices and smaller servings.

FAQ

Can I use all-purpose flour instead of cake flour?

Yes. Use the substitution listed above: for each cup of cake flour, measure 1 cup minus 2 tbsp all-purpose flour and add 2 tbsp cornstarch. Sift well.

What if I don’t have buttermilk?

Stir 1 tbsp lemon juice or white vinegar into 1 cup milk. Let it sit 5 minutes, then use.

How do I keep the colors from bleeding?

Use gel colors, avoid overmixing, and let layers cool fully before stacking. Add only a thin frosting layer between layers.

Can I bake this as cupcakes?

Yes. Divide tinted batter into lined muffin pans, filling 2/3 full. Bake at 335°F for 16–19 minutes.

My layers domed. What should I do?

Level with a serrated knife once cool. Next time, bake at 335°F and use cake strips for even tops.

How do I get super white frosting?

Use clear vanilla, whip in 1–2 tbsp heavy cream, and add a tiny drop of violet gel to counter yellow tones.

Can I make fewer colors?

Absolutely. Go with three or four layers for a faster build—red, yellow, blue still looks bold.

Conclusion

This easy rainbow cake delivers tender layers, bold color, and a creamy vanilla finish without stress. Mix, tint, bake, and stack—then watch the smiles when you slice. If you try it, drop a comment with your favorite variation or decorating twist. Happy baking!

Easy Super Moist Rainbow Cake Recipe

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Ingredients

  

Ingredients

Instructions

 

Instructions

• Prep pans: Grease and line three 8-inch round pans with parchment circles. Lightly flour the sides.
• Preheat: Set oven to 335°F (170°C) for even baking and flat tops.
• Room temp ingredients: Butter, eggs, and buttermilk should feel slightly cool but pliable.
• In a large bowl, whisk flour, baking powder, baking soda, and salt.
• In a stand mixer, beat butter and sugar on medium-high for 3 minutes until pale and fluffy.
• Beat in oil until glossy, about 30 seconds.
• Add eggs and egg white one at a time, mixing just to combine. Scrape bowl.
• Stir vanilla into the buttermilk.
• Add dry ingredients in three parts, alternating with buttermilk, starting and ending with dry. Mix on low until just smooth. Do not overmix.
• Weigh the batter or eyeball it into six equal portions in separate bowls.
• Tint each bowl with gel color: red, orange, yellow, green, blue, purple. Start with a little color, then build to intensity.
• Stir gently to avoid knocking out air.
• Three-pan method: Bake three colors at a time. Spread each color into a thin even layer. Bake 12–15 minutes until the center springs back. Cool 10 minutes in pans, then turn out to cool completely.
• Single-pan method: If you have one pan, bake layers one at a time, re-lining the pan each time. Keep colored batters covered so they don’t dry out.
• Beat butter on medium-high for 2 minutes until creamy.
• Add powdered sugar, salt, and vanilla. Mix on low until combined.
• Add cream a tablespoon at a time until the frosting looks smooth and spreadable. Whip on medium-high for 1–2 minutes for fluff.
• Place the purple layer on a board. Add a thin layer of frosting.
• Stack blue, green, yellow, orange, then red, frosting lightly between each. Use about 1/3 cup frosting per layer to avoid slipping.
• Chill the stacked cake for 15 minutes to set.
• Apply a thin crumb coat. Chill 15 minutes, then finish with a smooth final coat.
• Decorate with sprinkles, swirls, or keep it sleek and white.