Rainbow Layer Cake

The Rainbow Layer Cake is a colorful and celebratory dessert featuring six distinct layers, each dyed a different color of the rainbow. Between each layer is a generous spread of smooth buttercream frosting, creating a beautiful and eye-catching centerpiece perfect for birthdays, celebrations, or any festive gathering. Despite its elaborate appearance, this cake is relatively straightforward to prepare and delivers a classic, moist vanilla flavor.

Why You’ll Love This Recipe

This Rainbow Layer Cake is more than just a treat—it’s a statement piece. Whether you’re hosting a party or looking to surprise someone special, this cake adds a touch of joy and wonder. Each layer is light and fluffy, and the buttercream adds just the right amount of sweetness and creaminess. It’s a delightful project for bakers who love to create visually impressive desserts without overly complex techniques.

Ingredients

(Tip: You can find the complete list of ingredients and their measurements in the recipe card below.)

For the Cake Layers:

• All-purpose flour

• Baking powder

• Baking soda

• Salt

• Unsalted butter, softened

• Granulated sugar

• Egg whites, room temperature

• Vanilla extract

• Whole milk, room temperature

• Gel food coloring: red, orange, yellow, green, blue, purple

For the Buttercream Frosting:

• Unsalted butter, softened

• Powdered sugar

• Vanilla extract

• Heavy cream or milk

• Salt

Directions

1. Preheat the oven to 350°F (175°C). Grease and line six 8-inch round cake pans with parchment paper. If fewer pans are available, bake in batches.

2. Mix dry ingredients: In a medium bowl, whisk together flour, baking powder, baking soda, and salt.

3. Cream butter and sugar: In a large mixing bowl, beat butter and sugar until light and fluffy.

4. Add egg whites and vanilla: Gradually beat in egg whites, then stir in vanilla extract.

5. Combine dry and wet ingredients: Alternate adding the dry ingredients and milk to the butter mixture, mixing until just combined.

6. Color the batter: Divide batter evenly into six bowls. Tint each with a different gel food coloring to create red, orange, yellow, green, blue, and purple batters.

7. Bake: Pour each colored batter into separate pans and bake for 15–20 minutes or until a toothpick comes out clean.

8. Cool completely: Allow cake layers to cool in pans for 10 minutes before transferring to wire racks to cool completely.

9. Make the buttercream: Beat butter until creamy. Gradually add powdered sugar, then mix in vanilla, salt, and enough cream to reach a smooth, spreadable consistency.

10. Assemble the cake: Start with the purple layer and spread frosting over the top. Continue layering in order: blue, green, yellow, orange, and red, with frosting between each.

11. Frost the cake: Apply a thin crumb coat around the cake. Chill for 30 minutes. Add a final smooth layer of frosting.

12. Decorate as desired: Use sprinkles, piped decorations, or edible glitter for a festive finish.

Servings and Timing

• Servings: 12

• Prep Time: 1 hour

• Bake Time: 15–20 minutes per batch

• Cooling and Assembly Time: 1–1.5 hours

• Total Time: Approximately 3 hours

Variations

• Flavor options: Add citrus zest, almond extract, or coconut extract to individual layers for added dimension.

• Chocolate frosting: Swap the vanilla buttercream for chocolate frosting for a richer contrast.

• Vegan version: Use plant-based milk, egg replacer, and vegan butter to make a fully vegan rainbow cake.

• Mini cakes: Bake the batter in smaller pans to create individual mini rainbow cakes.

Storage/Reheating

• Room temperature: Store at room temperature in an airtight container for up to 2 days.

• Refrigeration: Keep in the fridge for up to 5 days. Bring to room temperature before serving.

• Freezing: Unfrosted layers can be frozen for up to 3 months. Wrap tightly in plastic wrap and place in a freezer-safe bag.

• Reheating: Let frozen layers thaw overnight in the refrigerator before decorating.

FAQs

How do I keep the cake layers from drying out?

Do not overbake, and be sure to cool the cakes properly before wrapping or frosting them.

Can I use natural food coloring instead of gel?

Natural food colorings work, but the colors may be less vibrant than those achieved with gel dyes.

What if I only have two cake pans?

You can bake the layers in batches. Just keep the unused batter covered and at room temperature between bakes.

Can I make the cake layers ahead of time?

Yes. Bake them a day or two in advance, then wrap and refrigerate or freeze until ready to assemble.

Is there a difference between gel and liquid food coloring?

Gel food coloring is more concentrated and won’t water down your batter, making it ideal for vibrant cake layers.

What’s the best way to frost the cake smoothly?

Use an offset spatula and a cake turntable. Chill the crumb coat before applying the final frosting layer.

Can I make this cake gluten-free?

Yes, substitute a 1:1 gluten-free flour blend in place of all-purpose flour.

Will the cake taste different because of the food coloring?

No, gel food coloring does not affect the flavor of the cake.

Can I use whole eggs instead of egg whites?

Egg whites help keep the cake light in color and texture. Using whole eggs may slightly affect both.

What can I use instead of buttercream frosting?

Whipped cream frosting or cream cheese frosting are great alternatives, depending on your flavor preference.

Conclusion

The Rainbow Layer Cake is a striking and joyful dessert that combines visual appeal with classic vanilla flavor. With its soft, colorful layers and smooth buttercream, it’s an ideal choice for any festive event. Whether you’re celebrating a birthday or simply indulging in a baking project, this cake is sure to leave a lasting impression.