Radiant Rainbow Graduation Cake

Name: Radiant Rainbow Graduation Cake
Prep time: 30 min
Cook time: 30 min
Total time: 1 h
Yield: 12 servings
Ingredients: 3 cups all-purpose flour; 2 ½ cups granulated sugar; 1 cup unsalted butter, softened; 5 large eggs; 1 cup whole milk; 1 tablespoon vanilla extract; 1 tablespoon baking powder; 1 teaspoon salt; Food coloring (red, orange, yellow, green, blue, purple); 2 cups unsalted butter, softened; 6 cups powdered sugar; 1/4 cup heavy cream; 1 tablespoon lemon zest; 1 teaspoon vanilla extract; Pinch of salt

Highlighted under: Indulgent Dessert Recipes

I’ve always believed that a celebration deserves a cake that shines as brightly as the moment. I created this Radiant Rainbow Graduation Cake to honor graduation achievements, and it did not disappoint! With vibrant layers of colorful sponge and a luscious buttercream frosting, this cake is a feast for both the eyes and the palate. Each slice reveals a beautiful spectrum of colors, symbolizing the joy and excitement of graduation. Perfect for gathering friends and family, this cake will leave everyone in awe, making it an unforgettable centerpiece at any celebration.

Created by

Emily

Last updated on 2026-02-21T20:26:19.714Z

When I decided to bake this cake for my friend's graduation party, I wanted to incorporate vibrant colors and flavors that would evoke joy. I experimented with a classic vanilla cake base, adding food coloring to create those mesmerizing rainbow layers. The result was not only visually stunning but incredibly delicious!

To elevate the flavor, I zested some fresh lemons and added that to the buttercream frosting. I found that the citrusy zing perfectly complemented the sweetness of the cake, creating a balance that everyone raved about. This cake captures not just the essence of celebration, but also the spirit of new beginnings.

Why You Will Love This Recipe
Vibrant layers that burst with color and flavor
Luxurious buttercream frosting that adds a zesty kick
A memorable centerpiece for any celebration

The Importance of Proper Cooling

Cooling your cake layers properly is crucial to achieving a beautiful and sturdy cake. After baking, allow the layers to cool in the pans for about 10 minutes before transferring them to a wire rack. This helps the cakes maintain their shape. If you skip this step, the layers might crack or crumble when you try to remove them.

It's essential to let the cake layers cool completely before frosting. I recommend waiting at least 1 hour. Warm cake layers can cause the buttercream to melt, leading to a messy finish. You can speed up the cooling process by placing the layers in the refrigerator for a short period, as long as they aren’t too warm.

Coloring with Purpose

When adding food coloring, a little goes a long way. Start with a few drops and mix thoroughly to see the color develop. You can always add more if needed. For the most vibrant colors, I suggest using gel food coloring, as it provides a more potent hue compared to liquid versions. This ensures each layer stands out spectacularly when sliced.

Mix each colored batter gently until just combined to avoid overworking the gluten, which can make the cake tough. It's also a good idea to use separate utensils for each color; this keeps your colors from muddying together and allows for clear, distinct layers in your finished cake.

Ingredients

For the Cake Layers

3 cups all-purpose flour
2 ½ cups granulated sugar
1 cup unsalted butter, softened
5 large eggs
1 cup whole milk
1 tablespoon vanilla extract
1 tablespoon baking powder
1 teaspoon salt
Food coloring (red, orange, yellow, green, blue, purple)

For the Buttercream Frosting

2 cups unsalted butter, softened
6 cups powdered sugar
1/4 cup heavy cream
1 tablespoon lemon zest
1 teaspoon vanilla extract
Pinch of salt

Preparation Steps

Instructions

Steps to Make the Cake

Prepare the Cake Batter

Preheat your oven to 350°F (175°C). Grease and flour six 8-inch round cake pans. In a mixing bowl, cream together the butter and sugar until light and fluffy. Add the eggs one at a time, beating well after each addition. Mix in the milk and vanilla extract. In another bowl, whisk together flour, baking powder, and salt. Gradually add the dry ingredients to the wet mixture until just combined.

Color and Bake

Divide the batter equally into six bowls. Add food coloring to each bowl to create a different color of batter. Starting with purple and moving to red, pour each colored batter into the prepared cake pans. Bake for 25-30 minutes or until a toothpick comes out clean. Let the layers cool in the pans for 10 minutes before transferring to wire racks to cool completely.

Make the Buttercream Frosting

In a large mixing bowl, beat the softened butter until creamy. Gradually add powdered sugar and mix until smooth. Add heavy cream, lemon zest, vanilla extract, and salt. Beat until fluffy and light.

Assemble the Cake

Once the cake layers are completely cool, place one layer on a serving plate. Spread a generous amount of buttercream frosting on top, then add the next layer. Repeat for all layers. Once assembled, use the remaining frosting to cover the entire cake.

Decorate and Serve

To add some flair, you can pipe extra frosting on top and sprinkle edible glitter or confetti. Slice, serve, and enjoy this stunning Radiant Rainbow Graduation Cake at your celebration!

Enjoy!

Pro Tips

For a more intense color, use gel food coloring instead of liquid. Make sure the cake layers are completely cool before frosting to prevent melting.

Storage Tips

Once your Radiant Rainbow Graduation Cake is fully assembled, it can be stored in an airtight container at room temperature for up to 3 days. However, if your environment is particularly warm or humid, sealing it in the refrigerator is a better option to ensure the buttercream doesn't soften excessively.

For longer storage, you can freeze the unassembled cake layers. Wrap each layer tightly in plastic wrap and then place them in a freezer-safe bag. They will keep well for up to 2 months. When you're ready to use them, thaw the layers in the refrigerator overnight.

Adapting for Dietary Needs

If you're looking to accommodate dietary restrictions, consider substituting ingredients in this recipe. For a gluten-free cake, use a 1:1 gluten-free all-purpose flour blend. Just be sure it contains xanthan gum for improved texture, as standard flour’s gluten contributes to the cake's structure.

To make the buttercream dairy-free, try using a plant-based butter alternative and coconut cream instead of heavy cream. These substitutions may slightly change the texture and flavor but will still provide a deliciously creamy frosting.

Questions About Recipes

→ Can I make the cake ahead of time?

Yes, you can bake the layers a day in advance and store them in the fridge. Just frost them on the day of serving.

→ What can I use instead of butter in the frosting?

You can use a vegan butter substitute or cream cheese for a different flavor and texture.

→ How do I store leftovers?

Keep the leftover cake in an airtight container in the fridge for up to 5 days.

→ Can I freeze this cake?

Yes, the fully assembled cake freezes well. Wrap it tightly and freeze for up to 3 months.