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5 from 1 vote

Rainbow Surprise Loaf Cake

This Rainbow Surprise Loaf Cake is such a fun and easy recipe to make for a birthday party!
Prep Time20 mins
Cook Time50 mins
Course: Dessert
Cuisine: American
Keyword: rainbow surprise loaf cake, rainbow surprise loaf cake recipe
Servings: 12 servings
Calories: 639kcal
Author: Jill


Surprise loaf Cake:

  • 2 boxes vanilla cake mix
  • 6 eggs
  • 1 C canola oil
  • 1 C water
  • Purple, pink, blue and teal gel coloring

Vanilla royal icing:

  • 3 whites
  • 1/4 tsp cream of tarter
  • 3 C powder sugar plus 1/2 c on stand by
  • 1 tsp vanilla
  • Pink and Green gel food coloring
  • Confetti Sprinkles


  • Make the 2 white cake mixes according to the boxes
  • Mix one box into a medium bowl and the other into another medium bowl.
  • Take the second white bowl and split it into 4 bowls.
  • Take the color and add a color to one bowl each.
  • Scoop 1 color of the 4 batters into one piping bag.
  • Repeat with remaining 3 colors
  • Using the cookie sheet with parchment paper, take 1 of the piping bags, cut the tip off, pipe one line of the color batter from side to side. Repeat with the other colors. Example: purple, pink, teal, green, purple, pink, teal, green until the pan is covered in colorful lines.
  • Bake the cake at 350 degrees for for 20 minutes or until cake is baked and a toothpic comes out clean.
  • Take the star cookie cutter and cut out star shapes.
  • Take your loaf pan and spray pam all over it.
  • Pour some of the plain cake batter into the bottom of the pan
  • Take your star shapes and place them standing up into the batter that is already in the loaf pan.
  • Slowly pour the remaining batter around the stars so that when it bakes, the batter will bake over the stars and you won't see them.
  • bake at 350 for 30-40 minutes or until a toothpick comes out clean
  • set aside and let cool before taking out and placing on your favorite serving dish.


  • Combine all ingredients, except the colors and sprinkles, into a standing mixer and beat until stiff peaks form.
  • Add the extra half cup of powder sugar if the royal icing looks like soup
  • once stiff peaks form split into 3
  • add the two colors into the bowls, mix until you have your desired color, leaving one bowl white
  • Add the white icing first over the loaf and then drizzle the pink and green
  • add the sprinkles
  • enjoy


Calories: 639kcal | Carbohydrates: 100g | Protein: 7g | Fat: 24g | Saturated Fat: 4g | Cholesterol: 82mg | Sodium: 643mg | Potassium: 106mg | Fiber: 1g | Sugar: 66g | Vitamin A: 120IU | Calcium: 201mg | Iron: 2.1mg