Geode Cake with Silicon Mold
The latest geode inspired cake trends in cake decorating have been the rage and rightfully so. However, not everyone wants to carve a hollow into the pretty perfect cake layers. Here is how I made this geode cake with silicon mold, not need to carve and not stuffing rock candy into the cake. I hope you find this geode cake tutorial useful.

What is a geode cake
Geode cakes are inspired by Geodes which are hollow rocks filled with sparkling crystals and minerals. These geode cakes are now in trend and most fun to create.
To make a geode cake you would essentially need to carve a hollow inside layered cake and line that hollow with rock candy. This can then be colored with shades of purple or turquoise for that geode effect.
About this cake
I recently was asked to make a Bat Mitzvah cake. The birthday girl wanted a geode inspired cake but the mom wasn’t very thrilled with the idea of a beautiful three tier cake being hollowed and filled with rock candy. Not to mention she was already taking a risk of ordering less servings.
Furthermore, we have hot summers here in Middle East which means 45C / 113 F is not uncommon for the month of may. As a cake decorator carving that geode cake and traveling 45 minutes to an hour in this humidity was not something I would look forward to.
Making a geode cake using a mold seems like the best option. So, I made a small single tier dummy with the effect and showed the mother and daughter. Needless to say, they were thrilled and opted that I make this cake.
As luck would have it, Marvelous Molds also sent me two new molds from their new collection to play with.

Ruffles, ruffles and more ruffles.
I love ruffles and yes, I do love making them on the cake too. But ruffles take time. Often when you add extra time to the cost of the cake it ends up being expensive. I’ve often had people choose a different design so they can lower the cost of their cake.
With these two new molds by Marvelous Molds, the process gets down to minutes instead of hours. If you see the video you will see how easy they are to make. By the way, ruffles do use a lot of fondant, whether it’s made the old school method one strip at a time or in a mold. If done well, the ruffles in these molds turn out very elegant and beautiful. Today I am using the Scrunch Ruffles Onlay from the Simpress Collection. Soon I plan to use the Rosette Ruffles onlay and I’ll share that cake with you as well.

Cake flavors and recipes
- The bottom tier is a square cake using my chocolate mud cake with chocolate ganache
- The double barrel is two 6-inch cakes stacked as one tier. The bottom is Earl gray cake and the top is a butterscotch cake both frosted with Swiss meringue buttercream
- The top is a tall 4 inch strawberry with Swiss meringue buttercream.
- Today I have used my marshmallow fondant – It does have a better stretch so works great for the double barrel cake.

Step by step instructions
Scrunch ruffles – bottom tier
- For the bottom tier, I have used the scrunch ruffles mold by Marvelous Molds.
- Dye fondant in the desired colors and roll a thick rectangle the same size as the mold

- Dust the mold liberally with cornstarch and shake off the excess.
- Place the fondant on the mold and using your fingers gently press down on the fondant so it goes into the mold. This will give a better impression.

- Flip the mold over and peel the mold away from the fondant. Peeling the mold away prevent the fondant from stretching.

- You can put the fondant on the cake directly using the mold OR
- Place it on a parchment lined baking tray as I have.
- Make as many pieces as you need for the cake I used 2 on each side of the cake so I made 8.
- Let the pieces chill in the fridge until firm – 5 minutes
- Place one piece of ruffle on the cake and cut another to join at two ends. The molds are designed so the ends fit nicely together creating a seamless pattern.
- I used a thin strip of fondant in purple at the edges

Creating the geode with silicon mold
- For the geode effect, I have used the Diamonds in Rough silicon mold by Marvelous Molds
- Using white fondant roll a thick rectangle the same size as the mold
- Dust the mold liberally with cornstarch and shake off the excess.
- Place the fondant on the mold and using your fingers gently press down on the fondant so it goes into the mold. This will give a better impression.
- Flip the mold over and peel the mold away from the fondant. Peeling the mold away prevent the fondant from stretching.

- Make three or as many necessary for your cake.
- Place it on a parchment lined baking tray as I have and chill in the fridge.
- Cut a piece of parchment paper in a long oval shape – lay it against the cake and create a template the size and length of the geode you need.
- Use this template as a guide and cut the molds to a long oval shape
- Attach it to the cake.
- Add a thin white long sausage all around as a border

Coloring the geode shape
- As shown in the video I have used purple and a bit of fuchsia and white with Vodka.
- Start painting from the inside out – darker on the inside lighter on the out.
- You will need to add colors in layers – adding more as necessary to get the desired effect.
- Let dry then brush with luster dust and vodka for that shimmer effect.

Finish the cake
- Don’t forget to cover the board
- And tie a ribbon around the board.
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How to make a Geode Cake using Silicon Mold
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Video
Ingredients
- 8 inch Chocolate Mud Cake (3 square layers)
- 6 inch Earl grey cake (3 layers)
- 6 inch Butterscotch cake (3 layers)
- 4 inch Strawberry cake (4 layers)
- 2 kgs Homemade Fondant (White)
- 1 kg Swiss meringue buttercream
- 1 kg Cake Decorators Dark Chocolate ganache
Instructions
HOW TO MAKE A GEODE CAKE WITH SILICON MOLD?
SCRUNCH RUFFLES – BOTTOM TIER.
- For the bottom tier, I have used the scrunch ruffles mold by Marvelous Molds.
- Dye fondant in the desired colors and roll a thick rectangle the same size as the mold
- Dust the mold liberally with cornstarch and shake off the excess.
- Place the fondant on the mold and using your fingers gently press down on the fondant so it goes into the mold. This will give a better impression.
- Flip the mold over and peel the mold away from the fondant. Peeling the mold away prevent the fondant from stretching.
- You can put the fondant on the cake directly using the mold OR
- Place it on a parchment lined baking tray as I have.
- Make as many pieces as you need for the cake I used 2 on each side of the cake so I made 8.
- Let the pieces chill in the fridge until firm – 5 minutes
- Place one piece of ruffle on the cake and cut another to join at two ends. The molds are designed so the ends fit nicely together creating a seamless pattern.
- I used a thin strip of fondant in purple at the edges
CREATING THE GEODE WITH SILICON MOLD
- For the geode effect, I have used the Diamonds in Rough silicon mold by Marvelous Molds
- Using white fondant roll a thick rectangle the same size as the mold
- Dust the mold liberally with cornstarch and shake off the excess.
- Place the fondant on the mold and using your fingers gently press down on the fondant so it goes into the mold. This will give a better impression.
- Flip the mold over and peel the mold away from the fondant. Peeling the mold away prevent the fondant from stretching.
- Make three or as many necessary for your cake.
- Place it on a parchment lined baking tray as I have and chill in the fridge.
- Cut a piece of parchment paper in a long oval shape – lay it against the cake and create a template the size and length of the geode you need.
- Use this template as a guide and cut the molds to a long oval shape
- Attach it to the cake.
- Add a thin white long sausage all around as a border
COLORING THE GEODE SHAPE
- As shown in the video I have used purple and a bit of fuchsia and white with Vodka.
- Start painting from the inside out – darker on the inside lighter on the out.
- You will need to add colors in layers – adding more as necessary to get the desired effect.
- Let dry then brush with luster dust and vodka for that shimmer effect.
FINISH THE CAKE
- Don’t forget to cover the board
- And tie a ribbon around the board.
Conversions Used
1 lb = 453 grams, 1 cup = 240 ml, 1 stick = 113g, 1 tbsp= 15 ml, 1 tsp= 5 ml,
The nutrition information and metric conversion are calculated automatically. I cannot guarantee its accuracy. If this data is important to you please verify with your trusted nutrition calculator. Thank you
Such a lovely cake, decorative and elegant & love the instructions.
Thank you, Megha.
I always see these geode cakes – they are so pretty but look so complicated!! I love that you can make them with a mold!
Thank you, Carrie.
Wow! Making tiered cakes is not easy but yours looks just perfect!
Thank you, Julia.
Wow cake looks incredibly beautiful and unique! It really impressed me! Great instruction. Thanks!
Thank you, Mary.
This is really gorgeous!! A perfect cake for any occasion!
Thank you, Toni.