Inside Out Rainbow Cake

Character cakes are a great way to incorporate animated characters to your favorite recipes. In the past, I’ve done it with characters like Peppa Pig, but also some iconic Disney characters like Elsa and Anna. Since the release of the Disney and Pixar’s film Inside Out, I’ve been getting tons of requests to show you guys a recipe inspired by the movie, and what better way than with a character cake. I decided to go with my favorite Inside Out character Bing Bong, and make a 5 layered rainbow cake around him! This is my Inside Out Rainbow Cake!

Straight lines are key to making this a successful cake. Really pay close attention to your template and your paper to make sure that the sanding sugar doesn’t cross into other colors.


  1. Use a serrated edge knife to carve your cake layers. Level off the top of your cake and remove any brown from the outside (including the bottom). Do this for all five layers of cake.
  2. With an offset spatula, smear frosting directly onto the center of your cake board. Lay the purple layer of cake right on top of it. Add a crumb coat to the top of the cake, then add a thicker coat on top of that.
  3. Place your blue layer on top of your purple and repeat the previous step. Then, continue to stack your cake layers with your green layer, then yellow. Add your red layer to the top, but do not frost.
  4. Use a serrated edge knife to  trim off the brown edges from the cake.

    inside out shave

  5. Add a crumb coat to the entire outside of the cake.  Move your offset spatula back and forth while frosting to catch those crumbs. Then, add a layer of frosting to the top of the cake. Transfer to the fridge to set.
  6. Dollop a spoonful of white chocolate onto a small piece of parchment paper to create a flat and even circle. Give it a tap on the bench to level off the chocolate. Place your Bing Bong figurine right in the middle. Set him aside.

    bing bong

  7. Take 2 test tubes and fill them with gumballs. Join the two halves together. Add a piece of tape and roll it around so that it’s completely smoothed and attached. Repeat so that you have 5 total test tubes. NOTE: Make sure each top gum ball coordinates with a cake color (red, yellow, green, blue, and purple).

    tape inside out cake

  8. Take your cake out of the fridge. Add another layer of buttercream frosting. Use a ruler to scrape away any excess frosting.
  9. For this step, you have to work somewhat quickly so that your buttercream doesn’t begin to set and form a crust.  Place your template directly on the top of the cake.  Place your red sanding sugar in the open space of the template. Use your fingers to spread it out. Make sure it doesn’t go under your template into another section. Scrape back any excess onto the template, and discard.

    red sanding sugar inside out

  10. Place a piece of paper on the edge of your cake so that it lines up with the sanding sugar. Then, sand the sides of the cake using the paper as a guide. Repeat on the other side.

    sanding inside out cake

  11. Adjust your wheel and repeat the previous two steps with your remaining colors.
  12. Once your cake is completely sanded, take a small circle cutter and cut down into the cake where two colors meet. Place your test tube up to make sure it can fit in that space. Repeat this for each edge where the two colors meet.

    circle cutter inside out cake

  13. Use a pastry brush to paint white chocolate directly onto where you’ve taped the two test tube halves together. Do this for all five test tubes.
  14. Place frosting into the divot you made with your circle cutter. Leave a bit of space at the top without frosting. Place the test tube with the coordinating top color in place. Hold the test tube for support if needed. Repeat with the rest of the divots.

    test tube inside out cake

  15. Use a spoon to scrape away some of the sanding sugar from the center of the top of the cake where the five colors meet. Then, carefully add some melted white sugar to the center of the cake. Place Bing Bong directly in the center.

    final inside out cake

I hope this cake brings you joy…and a bunch of other emotions! 😊

-For the printable recipe click here:

What You’ll Need:  

  • 5 x vanilla cake layers (7″), each tinted a different colour (Red, Yellow, Green, Blue & Purple) ** This equates to 3 of my vanilla cake recipes **
  • 2 batches of vanilla buttercream frosting
  • Sanding sugar in Red, Yellow, Green, Blue & Purple
  • Gumballs (about 60) ** make sure they’re smallish ones and can fit in your test tubes
  • Melted white candy melts or compound chocolate *Compound chocolate doesn’t contain cocoa butter in the ingredients list*

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