Psychedelic Rainbow Cake

Dial up the fun at any celebration with a far-out cake that's rainbowed from top to bottom.

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Psychedelic Rainbow Cake

This psychedelic cake has a double dose of colorful layers to make it a true technicolor treat for the eyes. Follow these steps to make your own.

What You'll Need

Food:

 ● 1 recipe white cake batter (choose any recipe you like)
 ● Vanilla buttercream frosting (use the large batch recipe included or 3 store-bought cans)
  ○ 6 cups (12 sticks) unsalted butter, softened
  ○ 2 pounds (1 bag) confectioners' sugar
  ○ 2 tablespoons heavy cream
  ○ 1 tablespoon vanilla extract
  ○ 1/2 teaspoon table salt
 ● Food coloring: Red, Orange, Yellow, Green, Blue

Tools:

 ● Offset spatula
 ● Plastic piping bags (and rubber bands to close them)
 ● Star decorating tips

Prepare Cake Batter

Preheat the oven to 350 degrees F. Line five 6-inch cake pans with parchment paper and coat with cooking spray. Prepare your choice of white cake batter as directed and divide the batter between five bowls. Use food coloring to color each bowl of batter a different color of the rainbow (red, orange, yellow, green, and blue).

Bake the Cakes

Add each color of batter to a pan and bake 20 to 25 minutes. Allow the cakes to completely cool before you begin decorating.

Prep Frosting Colors

While the cakes are baking, make one large batch of buttercream frosting. Beat the butter for a few minutes on medium speed, preferably using a stand mixer with the paddle attachment. Mix on slow speed, gradually adding the confectioners' sugar 1 to 2 cups at a time, allowing each batch of sugar to incorporate into the butter before adding the next. Increase the speed to medium and add the vanilla, cream and salt. Beat for an additional 3 minutes.

Add 2 cups of frosting to five separate bowls; fill a large plastic piping bag with the leftover white frosting. Color each bowl of frosting a different color of the rainbow, just as you did with the white cake batter.

Frosting: Step 1

Working on a cake plate, add your blue cake round to the center and frost the top of the cake with blue frosting. Repeat with the green, yellow, and orange cake rounds and frosting.

Frosting: Step 2

Position the red cake on top, then frost the top and exterior of the cake with the white frosting.

Frosting: Step 3

Smooth the frosting with a spatula; refrigerate 30 minutes.

Decorating: Step 1

Add on a few small sections of white frosting around the cake.

Decorating: Step 2

Starting at the top side and working your way down the cake, use your spatula to add on the red, orange, yellow, green, and blue frosting colors. Don’t worry about adding it on cleanly as this technique creates a more fluid gradient - avoid perfect straight lines, let yourself have fun with it!

Decorating: Step 3

Once the frosting colors have been added, use a spatula to smooth the frosting.

Decorating: Step 4

For each color of frosting, insert a star piping tip into a plastic decorating bag and fill the bag with the colored frosting. Use a rubber band to close each bag.

[Note: If you don’t have piping bags, you can add on the frosting with your spatula.]

Decorating: Step 5

Add on the colors in a bullseye-fashion following the rainbow order to the top of the cake.

Decorating: Step 6

If you like the look of it, you can absolutely stop there.

Optional: Smooth Frosting on Top

Or if you’d like to have the psychedelic rainbow look on the top as well, smooth the frosting with a spatula. You can always add additional color to any areas that need more color.

Refrigerate Until It's Time to Serve

Place the cake back in the refrigerator until you’re ready to serve.

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