Rainbow Sheet Cake

Craving a vibrant and delicious cake that’s as fun to make as it is to eat? The Rainbow Sheet Cake is a perfect treat for birthdays, parties, or any occasion that needs a pop of color.

This soft and fluffy cake boasts six beautiful layers of bright colors, all packed into a simple sheet cake format. Paired with a luscious cream cheese frosting, this cake is as delightful in taste as it is in appearance!

Ingredients List

Creating a perfect Rainbow Sheet Cake requires a combination of key ingredients for the batter and the frosting. Let’s go over what you’ll need.

Cake Ingredients

• Baking spray with flour – To prevent sticking.
• 1 cup unsalted butter, softened – For a rich, buttery texture.
• 1 ½ cups white sugar – Adds sweetness and helps with a tender crumb.
• 3 large eggs (room temperature) – For structure and moisture.
• 2 teaspoons vanilla extract – Enhances the flavor.
• 3 cups enriched bleached cake flour – Ensures a soft, light cake.
• 1 tablespoon baking powder – Helps the cake rise properly.
• ½ teaspoon kosher salt – Balances the sweetness.
• 1 cup whole milk (room temperature) – Adds moisture and softness.
• Gel food coloring – Red, orange, yellow, green, blue, and purple for the rainbow effect.

Frosting Ingredients

• 1 (8-ounce) package cream cheese, softened – Creates a smooth and tangy frosting.
• ½ cup unsalted butter, softened – For creaminess.
• 3 cups powdered sugar, sifted – Adds sweetness and a silky texture.
• 1 teaspoon vanilla extract – Boosts the flavor.
• ⅛ teaspoon kosher salt – Balances the sweetness.
• Gel food coloring – Red, orange, and green for decorative accents.

Required Kitchen Tools

To make the baking process smooth and enjoyable, gather these essential tools before you start:

1. Stand Mixer or Hand Mixer – Helps mix the batter and frosting efficiently.
2. Mixing Bowls – For preparing the cake batter and dividing it for coloring.
3. Whisk and Spatula – For mixing dry ingredients and scraping the bowl.
4. 9×13-inch Baking Pan – The perfect size for a sheet cake.
5. Parchment Paper – Prevents sticking and makes for easy cake removal.
6. Measuring Cups and Spoons – Ensures accurate ingredient portions.
7. Toothpicks or Cake Tester – Checks for doneness.
8. Cooling Rack – Allows the cake to cool evenly.
9. Gel Food Coloring – Provides vibrant colors without affecting the batter’s consistency.
10. Offset Spatula – For spreading the frosting smoothly.

Cake Batter Preparation

Achieving a light and fluffy Rainbow Sheet Cake starts with a well-prepared batter. Follow these steps for the perfect base:

Mixing the Ingredients

1. Preheat the Oven – Set your oven to 350°F (175°C). Grease a 9×13-inch baking pan with baking spray and line it with parchment paper. Spray the parchment for extra non-stick protection.
2. Cream the Butter and Sugar – In a stand mixer fitted with a paddle attachment, beat the softened butter on medium speed until creamy (about 30 seconds). Gradually add the white sugar and beat until light and fluffy (2-3 minutes).
3. Incorporate the Eggs – Add the eggs one at a time, beating just until incorporated after each addition. Stir in the vanilla extract and mix until combined.
4. Combine Dry Ingredients – In a separate bowl, whisk together the cake flour, baking powder, and salt.
5. Alternate Adding Dry Ingredients and Milk – Gradually add the flour mixture to the butter mixture, alternating with milk (beginning and ending with the flour). Beat on low speed just until combined after each addition.

Coloring the Batter

1. Divide the Batter – Once the batter is fully mixed, divide it evenly into six small bowls.
2. Add Food Coloring – Using gel food coloring, tint each bowl a different color of the rainbow: red, orange, yellow, green, blue, and purple. Mix well until the colors are vibrant and evenly distributed.

Baking the Cake

Once your batter is divided and colored, it’s time to bake the cake to perfection. Follow these steps for even layers and a fluffy texture:

Layering and Baking

1. Layer the Batter – In your prepared 9×13-inch baking pan, gently spoon the colored batters in a random pattern or create swirls by layering them in the order of the rainbow. Use a toothpick or skewer to slightly swirl the colors for a marbled effect (optional).
2. Smooth the Top – Gently spread the batter with an offset spatula to ensure an even surface.
3. Bake the Cake – Place the pan in the preheated oven (350°F/175°C) and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
4. Cool the Cake – Let the cake cool in the pan for 10 minutes, then transfer it to a cooling rack to cool completely before frosting.

Making the Frosting

A smooth and creamy frosting will perfectly complement the vibrant cake layers. Here’s how to prepare it:

Cream Cheese Frosting Preparation

1. Beat the Cream Cheese and Butter – In a mixing bowl, beat cream cheese and butter together on medium speed until smooth and creamy (about 2 minutes).
2. Add Powdered Sugar – Gradually sift in the powdered sugar, beating on low speed to avoid mess, then increase to medium speed until fully incorporated.
3. Mix in Vanilla and Salt – Add the vanilla extract and kosher salt, then beat until smooth and fluffy.
4. Divide and Color (Optional) – If you’d like a decorative touch, divide a small portion of frosting and color it red, orange, and green for piping accents.

Frosting and Decorating the Cake

Now that your cake has cooled completely, it’s time to frost and decorate it for a stunning finish.

Frosting the Cake

1. Prepare the Cake – Ensure the cake is completely cool before applying frosting to prevent melting.
2. Spread the Frosting – Using an offset spatula, evenly spread the cream cheese frosting over the entire cake.
3. Smooth the Surface – For a clean look, smooth out the frosting with the spatula or leave it textured for a rustic finish.

Adding Decorative Elements

1. Colored Frosting Accents – Use the tinted red, orange, and green frosting to pipe small decorative swirls or shapes around the edges.
2. Rainbow Sprinkles (Optional) – Sprinkle some rainbow-colored sprinkles over the top for an extra festive touch.
3. Piping Borders – If you want a more refined look, pipe a border around the cake using a piping bag with a star tip.

Serving and Storage Instructions

How to Serve Rainbow Sheet Cake

• Slice the cake into even squares and serve at room temperature for the best texture and flavor.
• Pair it with a glass of cold milk or a scoop of vanilla ice cream for an indulgent treat.

Storing the Cake

• Refrigeration: Store any leftover cake in an airtight container in the refrigerator for up to 5 days. Let it sit at room temperature for a few minutes before serving.
• Freezing: To freeze, wrap individual slices in plastic wrap and store them in a ziplock bag for up to 2 months. Thaw overnight in the fridge before serving.

Conclusion

The Rainbow Sheet Cake is a show-stopping dessert that brings joy to any celebration. With its soft, buttery layers and creamy frosting, this cake is as delicious as it is eye-catching.

Whether for birthdays, parties, or just a fun baking project, this colorful creation is sure to impress! So, grab your mixing bowls and gel colors, and start baking your very own rainbow masterpiece today!