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Easy Rainbow Sprinkle Cake on White Plate with Yellow Background

Rainbow Sprinkle Cake

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Use this cake decorating tutorial to make an easy rainbow sprinkle cake. Colorful vanilla cake is covered in frosting, sprinkles and a fondant rainbow topper.
Course Dessert
Cuisine American
Keyword decorated cake, kids cake
Prep Time 10 mins
Cook Time 30 mins
Decorating time 1 d
Total Time 1 d 40 mins
Servings 8 Slices
Calories 1206
Author Abeer Rizvi



  • Bake cakes and let them cool completely.
  • While the cakes are cooling, prepare the frosting.
  • Place one cake on a serving plate.
  • Spread frosting on top.
  • Place the other cake on top and gently press it to secure into place.
  • Spread frosting all over the cake smoothly.
  • Place this plate of iced cake in a large, deep baking dish.
  • Cover the cake in sprinkles. Do the sides first and then, do the top. All the excess sprinkles will fall in the tray and can be reused.
  • Keep decorated cake aside.
  • Roll out marshmallow fondant in different colors.
  • Use a pizza cutter to cut out thin, even strips of each color.
  • Place your first fondant strip on a sheet of wax paper.
  • Then, brush very little water at the edge of this strip. 
  • Stick the next strip on this damp edge.
  • Brush water along the edge again and stick another strip.
  • Keep doing this until all your strips are stuck together. Keep aside.
  • Roll out some fondant in any color you want (I used dark blue).The length of this piece should be about the same as the length of your strips. 
  • Brush some water on top of this piece.
  • Gently pick up your strips arrangement and place them on top of this dark blue piece until it sticks into place.
  • Use a pizza cutter to cut out the irregular ends.
  • Use both your hands to gently curve this entire rainbow strip until it looks like an upside down "u"
  • Use a pizza cutter to cut the bottoms so they are straight.
  • To make clouds, roll out some light blue fondant and use a flower cutter to cut out two flower shapes. Then, use a knife to cut these flowers in half.  
  • Brush some water on both ends of the rainbow strip and stick the clouds in place.
  • Allow this rainbow to dry for 24 hours or until it gets hard. 
  • Once this rainbow is dry, flip it over and use some melted chocolate to stick toothpicks on both ends.
  • Push the rainbow into your cake. Enjoy!


  • Read all my tips above.
  • Leftovers can be stored in a sealed container in the fridge for up to 3 days. 


Calories: 1206kcal | Carbohydrates: 224g | Protein: 4g | Fat: 35g | Saturated Fat: 11g | Cholesterol: 77mg | Sodium: 734mg | Potassium: 134mg | Fiber: 1g | Sugar: 196g | Vitamin A: 116IU | Calcium: 58mg | Iron: 2mg