Go Back
+ servings
Sliced rainbow cake on a cake plate
Print Recipe
5 from 2 votes

Rainbow Cake Recipe

Learn how to make a Rainbow Cake from scratch. With super easy frosting technique no complicated piping and spreading needed. Soft almond meringue cake layers + marshmallow buttercream frosting.
Prep Time1 hr 40 mins
Cook Time2 hrs
Chill4 hrs
Total Time7 hrs 40 mins
Course: Dessert
Cuisine: American
Keyword: how to make a rainbow cake, rainbow cake recipe
Servings: 16 servings
Calories: 655kcal



  • 12 large egg whites
  • ¼ teaspoon salt
  • 1 ½ cups caster sugar (300g)
  • 28 tablespoon almond flour (224g)
  • 7 tablespoon flour (63g)
  • gel or paste food coloring: violet, indigo blue, blue, green, yellow, orange, red


  • 2 cups butter (452g)
  • 5 cups powdered sugar, sifted (600g)
  • 7 oz marshmallow cream (200g)
  • ¼ teaspoon salt
  • gel or paste food coloring: violet, indigo blue, blue, green, yellow, orange, red

OPTIONAL: Meringue for decoration (or replace with whipping cream, marshmallows, or sprinkles)

  • 4 large egg whites
  • 2 cups caster sugar (400g)
  • ¼ cup cold water (60ml)



  • Preheat oven to 320°F (160°C). 
  • With a pencil, draw seven 8“ (20,3cm) circles on parchment paper. Then flip over the parchment paper and place on baking sheets.
  • In a large mixing bowl with a handheld or stand mixer fitted with a whisk attachment, whisk egg whites and salt on medium-high speed until soft peaks form. Add sugar and whisk until glossy and stiff peaks form. Separate into 7 bowls equally. Color with violet, indigo blue, blue, green, yellow, orange, and red. Use as much gel or paste food coloring to your preference. Stir on medium-high speed just until combined and evenly colored.
  • With a wooden spoon fold into each color 4 tablespoon of almond flour and 1 tablespoon of flour carefully. Equally spread the meringue into the drawn circles till the outer lines. Make sure that they are almost the same in size and thickness. Bake one layer at the time for 17-20 minutes until dry and not too browned (very lightly browned is ok). Remove from the oven when dry to touch. Immediately flip over the parchment paper and remove the paper. Let cool to room temperature. 


  • Mix butter with a handheld or stand mixer fitted with a whisk attachment on medium-high speed until creamy for about 2 minutes. Add about 1 + ½ - 2 cups sugar at the time and mix on low speed until combined. Add marshmallow cream and salt and mix to combine. Separate the buttercream into 8 bowls. Color with violet, indigo blue, blue, green, yellow, orange, and red in the same tone as your meringue layers are. Add white coloring to lighten up the colors if needed. Color the 8th bowl with blue and white to create a sky blue tone for the top of the cake.

Assemble the cake

  • Place a closed 9" springform ring on a cake board or cake stand. Place the violet meringue cake layer in the middle of the ring. Spread a bit of frosting underneath the cake layer that it doesn't move around while frosting. Then spread the violet frosting on top of the cake layer and till the edges of the springform ring that the bottom is evenly covered. Watch out that you don't color the inside of the ring higher than the violet layer ends if you want to have straight lines on the sides. The accuracy of your work affects the shape of the lines on the sides of the cake.  Repeat with indigo blue, blue, green, yellow, orange, and finish with red on top. Spread remaining sky blue on top evenly. Chill for 4 hours or overnight.
  • OPTIONAL: Make the meringue: Fill a large saucepan ½ full with water and bring to a simmer over medium-low heat. In a heatproof bowl, whisk together egg whites, sugar, and water to combine. Place bowl oblique over the saucepan that the hot steam can escape around the sides of the mixing bowl. The bowl should not touch the simmering water. With a handheld mixer fitted with a whisk attachment, beat egg white mixture for 10 minutes or until shiny, glossy, and stiff peaks form. Make sure the meringue doesn't get too hot, or the egg whites will cook through, and the meringue will be lumpy. Remove from saucepan in-between to cool down a bit, if necessary. Not just that the meringue is lumpy in structure when cooked too hot, it also will smell and taste like cooked eggs whites instead like a meringue. Remove from heat and mix until cooled for about 5 minutes. 
  • Remove cake from the fridge. Run an icing spatula around the sides (push outwards against the ring while moving), open the springform ring and remove it. If necessary, level buttercream on the sides with the spatula by placing it on one side of the cake uprightly and spin around the cake without pushing too much against the cake. Pipe meringue with a piping bag fitted with a round tip on top of the cake. Go back and forth with the tip while piping to create an irregular cloud shape. Alternatively, decorate with whipping cream, marshmallows, or sprinkles on top instead of meringue if preferred. Store leftovers up to 3 days in the fridge.



I recommend reading the blog post and watching the 1-minute-video for better understanding.


Calories: 655kcal | Carbohydrates: 97g | Protein: 6g | Fat: 29g | Saturated Fat: 15g | Cholesterol: 61mg | Sodium: 331mg | Potassium: 64mg | Fiber: 1g | Sugar: 88g | Vitamin A: 710IU | Calcium: 34mg | Iron: 0.7mg