4.5 from 2 votes
You won't believe how easy it is to transform a 9x13 sheet cake into this delightful Rainbow Unicorn Cake with a colorful candy clay (modeling chocolate) mane and tail.
Rainbow Unicorn Cake
Prep Time
1 hr 30 mins
Cook Time
30 mins
Total Time
2 hrs
A tie-dye rainbow cake cut up into pieces then assembled and decorated to look like a unicorn with a rainbow colored candy clay tail and mane.
Course: Dessert
Cuisine: American
Keyword: rainbow cake, unicorn cake
Servings: 10
Author: Beth Jackson Klosterboer
  • 1 white cake mix
  • ingredients listed on box egg whites oil, water
  • red orange, yellow, green, blue, and purple food coloring
  • 3-4 cups white frosting
  • 2/3-3/4 cup pink frosting
  • 3-4 ounces white candy clay
  • edible gold luster dust
  • 1/2 ounce pink candy clay
  • 1 ounce black candy clay
  • 1 ounce each of red orange, yellow, green, blue, and purple candy clay
  1. Preheat oven to 350 degrees F.
  2. Spray a 9 inch by 13 inch cake pan with baking spray.
  3. Optionally, line the pan with parchment paper and spray the paper.
  4. Divide white cake batter into 6 bowls (about 3/4 cup in each).
  5. Color one bowl red, another orange, yellow, green, blue and purple.
  6. Pour batter into individual disposable pastry bags or large zip top bags.
  7. Snip off the tip of the bag and pipe squiggles of one color batter into the pan.
  8. Use about 1/3rd of the batter for the first layer.
  9. Continue piping squiggles of colors, layering the 6 colors a total of three times.
  10. Tap the pan on the counter a few times to level the cake batter and to remove any air bubbles.
  11. Bake according to instructions on the cake mix box.
  12. Remove cake and allow to cool completely.
  13. Invert cake onto a cutting board.
  14. Remove parchment paper if necessary.
  15. Cut cake in half so you have two 9 inch by 6 1/2 inch pieces.
  16. One piece will be the unicorn's body.
  17. Cut the other piece in half so you have two 6 1/2 by 4 1/2 inch pieces.
  18. One piece will be the unicorn's head.
  19. Cut two 2 inch by 3 inch pieces for the unicorn's legs.
  20. Discard or eat the remaining pieces.
  21. Assemble the cake by placing the 9 inch by 6 1/2 inch cake in the lower half of your cake board forming the unicorn's body.
  22. Set the 6 1/2 inch by 4 1/2 inch piece about 2 1/2 inches from the top edge of the larger cake forming the unicorn's head.
  23. Place the two leg pieces under the body piece about 3/4 of an inch from either edge.
  24. Spoon frosting into pastry bags fitted with #21 star tips.
  25. Pipe white stars over the large cake.
  26. Pipe stars over 3/4's of the head and legs, leaving room to pipe on pink hooves and a pink snout.
  27. Pinch off about 3 ounces of white modeling chocolate and form into a twisted unicorn horn.
  28. Brush with edible gold luster dust and attach to the cake near the right side of the top edge of the head.
  29. Roll the remaining white candy clay to about 3/16th inch thickness. Cut out an ear using a 1 1/2 inch wide by 2 1/2 inch long tear drop cookie cutter or a knife.
  30. Roll out the pink candy clay to about 1/16th inch thickness.
  31. Cut a smaller tear drop shape.
  32. Use a small dab of water to attach the pink teardrop to the center near the lower edge of the white teardrop to form the unicorn's ear.
  33. Set the ear aside to dry for about 10 minutes.
  34. Roll out the black candy clay and cut out a 2 1/4 inch circle then cut just a thin edge from around the circle to create a thin moon shaped eye.
  35. Cut a small 3/4 inch round out of the black and do the same creating a nose.
  36. Cut four small rectangles then shape them into teardrop shaped eyelashes.
  37. Roll the remaining black candy clay into a long thin log for the unicorn's mouth.
  38. Use a dab of frosting to attach the candy ear to the upper right corner of the unicorn's head.
  39. Press the eye onto the cake to the left below the ear.
  40. Then press the four eyelashes above the eye.
  41. Press the black log onto the pink frosting creating the unicorn's smile.
  42. Cut off any excess candy.
  43. Press the nose above the smile.
  44. Roll all the other colored candy clay pieces into 8 inch long logs.
  45. Press them all together in rainbow order: purple, blue, green, yellow, orange, and red.
  46. Cut the logs into one 3 inch side and one 5 inch side.
  47. Flatten the logs and roll them out to about 1/4 inch thickness.
  48. Shape the longer piece into a curved tail pinching together the left side.
  49. On the right side, cut the ends so that each color has a nice pointed shape.
  50. Cut the left edge of the other piece so that it's straight then cut the opposite side so that each color has a nice pointed shape.
  51. Attach the tail to the top corner on the right side of the unicorn's body and the mane to the right edge of the unicorn's head.