Best Geode Cake Recipe

The geode cake’s popularity has grown over the last few years. Its design mimics a rock formation with crystals in its cavity. It may seem challenging to make.

However, it’s possible to make this cake at home. This article provides a step-by-step geode cake recipe. The instructions are easy to follow and perfect for newbie bakers.

Why We Like This Recipe

This cake recipe is one of our favorites for the following reasons:

    • It’s easy to make: The cake may look too complicated to make. But it’s a straightforward recipe you can follow. You can pull it off with a few simple steps. Bakers of varying levels can manage the ins and outs of this cake recipe.
    • It requires a few ingredients: The cake itself utilizes common baking ingredients. You may even have them in your cupboard. The cake’s design requires only a few ingredients. These elements are readily available online, in the supermarket, or a baking supply store.
    • It’s a fun activity: Making a geode cake can be so much fun. It’s an activity you can do yourself or with a loved one. The thought of having a fantastic cake as a finished product adds to the excitement.

What You Will Need

crystal geode cake recipe


    • Sugar
    • Water
    • Gel food coloring
    • vodka
    • Fresh edible flowers
    • Meringue kisses
    • Sponge cake
    • Pink swiss buttercream frosting
    • White swiss buttercream frosting

Equipment Needed

    • Bamboo stick
    • Spatula
    • Tall glass jar
    • Wooden peg
    • Cake turntable
    • Side scraper
    • Paintbrush
    • Piping bag

How to Make Geode Cake

We encourage you to try doing this recipe even if it looks complicated. It’s easier than it seems. You can prepare the sponge cake and frosting beforehand. Doing things in advance can help you focus on the decoration part.

Step 1: Make a strong sugar syrup

purple geode cake recipe

Combine 100 grams of water with 300 grams of sugar. Bring it to a boil until the sugar dissolves. Then, please leave it to cool. Ensure that you have a thick, clear liquid for the best results.  

Step 2: Cover the stick with sugar

easy geode cake recipe

Dip a bamboo stick in water and roll it in some sugar. Leave it on the side to dry for a few minutes. Remember to complete this part. This process attracts the rock sugar, allowing the rock candy to grow nicely.  

Step 3: Prepare the rock candy setup

purple geode cake

Pour the sugar syrup into a tall glass jar. Then insert the stick into the jar. Secure it with a  wooden peg leaving an inch from the glass bottom. Make sure the rod is hovering inside the jar. Please prevent it from touching the bottom of the container.  

Step 4: Let the rock candy grow

geode cake fail

Leave the sugar set up for 5 to 7 days. This period allows the rock candy to grow along the stick. On the 7th day, you will get chunks of ice sugar crystals.  

Step 5: Prepare the sponge cake

galaxy geode cake

Get the sponge cake you’ve made in advance. It must be four to five layers high with a diameter of 6 inches. You can use your favorite butter, lemon, or vanilla sponge cake recipe. Crumb-coat the cake with buttercream.  

Step 6: Cover the cake with buttercream

how to make a geode cake

Smother the cake with a thick layer of white buttercream. Coat it evenly as you turn the revolving cake stand. Then use a side scraper to smoothen the sides and top of the cake.

Next, apply dollops of pink and purple buttercream. Spread the top and sides out to achieve a watercolor effect. Blend the colors using the scraper. Lastly, please put it in the refrigerator to allow the frosting to set.  

Step 7: Trim and tidy up the cake

pink geode cake

Once the cake is chilled, trim the excess buttercream. Use a sharp knife to cut hardened peaks on top of the cake. Cover imperfections with more buttercream. Then clean the sides with a scraper. Now is also the time to tidy up the cake board.  

Step 8: Create the geode effect

blue geode cake

Cut a triangle on one side of the cake. Take out each piece as you cut. Then mark a guide below the triangle. It will help you carve out a cavity to create a geode effect. You can decide at this point to reshape and widen the opening. Next, cover the cavity with a thick layer of buttercream.  

Step 9: Add the sugar crystals

geode cake ideas

Break the sugar crystals into smaller pieces. Then, stick them one by one in the cavity. Remember to fill in as many gaps as possible. Create a border with smaller details. After adding the crystals, refrigerate the cake for 5-10 minutes. Allowing it to chill will make the rok candy more stable.  

Step 10: Paint the sugar crystals

geode cake with flowers

Dilute gel food coloring in some vodka. Use this mixture to paint the sugar crystals. It’s best to color the deepest part a darker shade. Then paint the outer areas a lighter hue. This method gives the illusion of depth. Next, paint the border with gold food coloring. Lastly, add some meringue kisses and edible flowers on top of the cake.

Notes: It’s okay if some sugar chunks don’t stay on the stick. You will be breaking them into smaller pieces anyway.

Tips and Tricks

Here are some helpful hacks to help you achieve the best geode cake.

    1. Cool the syrup before using it to prevent the sugar on the stick from melting.
    1. Avoid touching the rock sugar candy setup so the crystal will form nicely.
    1. Leave the rock sugar candy mixture in a cool, dry place.
    1. Use gem colors for your sugar crystals. Emerald green and amethyst purple are your best bets.
    1. You can pipe some icing on top for a more dramatic effect.
    1. Aside from fresh edible flowers, you can also add a cake topper.
    1. Keep the cake board tidy. Use a clean washcloth to remove any frosting residue.

Common FAQs

Can you use store-bought sugar candy?

Yes, you can buy rock-sugar candy from baking supply stores. Finding them at a regular supermarket can be challenging. However, they’re easier to purchase online.

How long can you store the cake in the fridge?

It’s best to consume the cake within 2-3 days after making it. Store it in the fridge until you’re ready to serve.

What’s the alternative to using vodka?

You can use lemon juice to dilute the food coloring. Avoid using water as it is too thin. It will cause your paint to drip on the cake.


A nicely done cake can make any event extra- special. This geode cake recipe can bring life to your parties. It may seem daunting to create. However, the simple steps allow you to bake and decorate with ease. All you need are patience and some creativity.

Geode Cake Recipe

Course: Cake Recipes


Prep time


Cooking time





This easy-to-follow  geode cake recipe will be a crowd-pleaser at your next party


  • 100 grams water

  • 300 grams sugar

  • 5 layers of 6-inch sponge cake (5 layers of 6-inch cakes)

  • 300 grams white Swiss Buttercream frosting

  • 100 grams pink Swiss Buttercream frosting

  • 100 grams purple Swiss Buttercream frosting

  • 100 ml vodka

  • 1 small bottle purple food coloring gel


  • Prepare a strong sugar syrup by combining the sugar and water. Please bring it to a boil until thick. Then set aside.
  • Create a rock candy setup and let the sugar crystals grow. This process usually takes 5 to 7 days.
  • Coat the sponge cake layers with white buttercream frosting. Create a watercolor effect using pink and purple frosting.
  • Trim and clean the cake. Then, refrigerate it to harden the frosting.
  • Create a geode effect by carving out a cavity on the side of the cake. Cover the hollow part with frosting.
  • Decorate the cavity with sugar crystals. Then paint the rocks with purple food coloring. Next, paint the border with gold.
  • Add some finishing touches on the top. You may use meringue kisses, fresh edible flowers, or more sugar crystals.

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