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Octopus Cake

I had so much fun making my elephant cake last week I decided to continue my animal cake series. I’ve wanted to make an octopus cake for the longest time, and today was the day!!

image of an octopus cake made with colorful cake layers, buttercream and cake decorating rice krispie

I’ve avoiding making an octopus cake for a while because I was always scared of the tentacles (or more technically “arms”).

But thanks to the help of some cake decorating-friendly rice krispies (more on that below) this octopus cake is a lot of fun to make.

Making The Face for This Little Octopus

While I’m always team buttercream, there are some situations where using a bit of fondant just makes sense.

We’ve already put so much energy into making the cake layers and buttercream from scratch, a tiny but of fondant never hurt anyone.

I used a little bit of black and white fondant to make the little face on this octopus.

Small circle cutters can help you to get the shape of the eyes just right, and I love the adorable expression they give this cake.

image of an octopus cake being frosted and smoothed using an acetate sheet

Making this Octopus Cake with Rice Krispie Treats

You read that right! A batch of cake decorating-friendly rice krispies makes this challenging cake shape so much more manageable.

By omitting the butter that is in most rice krispie treats, these rice krispies set quite firmly once they’ve cooled.

This allows you to creatively and easily shape your cake. I used the same technique to make my Patrick Star cake I highly recommend if for larger shaped cake like this.

image of an octopus cake made being made with colorful cake layers, buttercream and cake decorating rice krispie

Substitutions and Swaps – Colorful Swirled Cake Layers

This octopus birthday cake uses quite a few ingredients and I know you might not have all of them on hand. Or if you have food allergies or restrictions, I’ve got you covered.

Below are some swaps and substitutions that can be made in this octopus cake recipe.

  • All Purpose Flour – This recipe turns out best with AP flour, but you can use a gluten free flour blend or cake flour if that’s all you have on hand. I don’t recommend using straight almond flour though!
  • Granulated Sugar – I do not recommend reducing the amount of sugar or changing the type of sugar, as it will change the texture of the cake layers.
  • Unsalted Butter – If you only have salted butter on hand you can use it in place of the unsalted butter in this recipe. Just be sure to omit the salt that this cake recipe calls for. You can also use vegan butter in its place!
  • Egg whites – If you don’t have egg whites on hand (I use the type out of the carton), you can use 4 whole eggs in place of the egg whites. Or you have an egg allergy you can use flaxseed eggs or an egg replacer.
  • Sour Cream – You can also use full fat yogurt, buttermilk, whole milk, or an alternative yogurt or milk (almond, soy, oat) if you’re dairy free.
  • Vegetable Oil – You can use any flavorless oil in this recipe. Canola or even sunflower oil would work great!
  • Vanilla Extract – Other extracts can also be used in place of the vanilla extract. Feel free to use almond, coconut, or even pistachio extract.
  • Gel food coloring – Natural food coloring (either liquid or powder) or liquid food coloring can be used if needed.
image of a purple and blue cake slice

Substitutions and Swaps – Vanilla Buttercream Frosting

  • Unsalted Butter – If you only have salted butter on hand you can use it in place of the unsalted butter. Just be sure to omit the salt that this frosting recipe calls for. You can also use vegan butter in its place!
  • Heavy Cream – Whole milk or alternative milk (soy, almond, oat) will work fine in this frosting recipe if that’s what you have on hand.
  • Vanilla Extract – Other extracts can also be used in place of the vanilla extract. Feel free to use coconut extracthazelnut extract, or even pistachio extract.
  • Gel food coloring – Natural food coloring (either liquid or powder) or liquid food coloring can be used if needed.
image of an octopus cake being frosted and smoothed using a small offset spatula

Coloring These Swirled Cake Layers & Frosting

Coloring these cake layers is totally optional, but it creates a fun surprise when you cut into the cake!

I used gel food coloring to make these cake layers purple and blue, along with my buttercream.

Liquid food coloring can work too, but it can throw off the consistency of the cake batter and frosting if you add too much.

Sometimes it can also give your frosting a bitter taste!

highly recommend using gel food coloring. Gel food coloring is concentrated so it allows you to use less. A couple squirts will create beautiful shades.

image of colorful swirled cake layers made with purple and blue cake batter

Gel food coloring is also thicker so it won’t change the consistency of the cake batter.  Americolor and Chef Master are my go-to brands of gel food coloring and I order them on amazon.

Natural food coloring (either liquid or powder) can be used in place of the gel food coloring! The colors won’t be quite the same, but it will still be beautiful.

Tips for Making the Best Octopus Cake:

  • Be sure to properly measure your flour (spoon into the cup measure then level) or use a kitchen scale to measure your dry ingredients.
  • Use gel food coloring to create vibrant colors of frosting without throwing off the consistency of the frosting or giving it a bitter taste.
  • Ingredients at room temp mix together better, so be sure you set out any cold ingredients ahead of time.
  • Mix your cake batter just until the ingredients are incorporated. This will ensure your cake layers are tender and soft.
  • Use an acetate sheet to help you get your final coat of frosting super smooth.
image of an octopus cake being frosted and smoothed using an acetate sheet
  • Chill your cake layers in the freezer for about 20 minutes before assembling the cake. This makes it easier to stack and frost.
  • Make this octopus cake vegan or dairy free if needed! Use your favorite type of dairy free milk to replace the buttermilk and heavy cream, and use vegan butter sticks in place of the butter. For the eggs I recommend using an egg replacer like this.
  • Be patient and give yourself lots of time! Sculpted cakes like this can be challenging. Take your time smoothing the frosting and adding on the details to this cake.
image of an octopus cake close up to show the detail on its arm or tentacle

Making This Octopus Cake in Advance & Storage Tips:

  • Make your cake layers in advance and freeze them. It breaks the process up and make it more approachable.
  • Make your frosting ahead of time too or save any leftover frosting. It can be stored in an airtight container in the fridge for up to a month. Or store it in the freezer for up to 3 months! Be sure to give it a good stir once it thaws to get the consistency smooth again.
  • A frosted cake can last in the fridge for up to a week. The buttercream locks in all the moisture, keeping the cake fresh and delicious.
  • If you cut into the cake and have leftovers, use any remaining frosting to cover the cut section to keep it moist. It can be stored in the fridge like this for up to a week.
image of an octopus cake made for a birthday party with a party hat

Let Me Know What You Think!

If you try this octopus birthday cake recipe, I’d love to hear what think of it! Let me know by leaving a rating below.

If you plan to share on social media, you can tag me @chelsweets! Also use the #chelsweets so that I can see your amazing creations on social media.

image of an octopus cake made with colorful cake layers and homemade buttercream

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