Geode cake tutorial – Fool’s Gold and Rose Quartz

Charlotte White ( is back once again to guide you through the hottest and tastiest new trends in cake design – this time geode cakes!

Brought to you by Restoration Cake


If you have not noticed the current trend for geode cakes, you must have been living underneath your own rock formation for the last few months! The trend was started by a bakery in Colorado, whose stunning wedding cake designs went viral – inspiring countless other cake designers and attracting mainstream press attention.

As a result of this, professional cake designers can be fairly certain that they will receive an order for a geode wedding cake at some point in the next few years. Remember that, while trends in the cake decorating world may come and go fairly quickly, the gestation period in the wedding world is much longer. Think about it, someone may have just seen their dream wedding cake on a tabloid website... but that does not mean that they are getting married in the immediate future. Get on top of these trends now and consider your own little spin on them ahead of the order!

I am currently working on another take on this trend, as you can tell from this recipe. This is the quick version, but a more intricate and time-consuming take on it is coming for the ambitious baker to tackle. This version uses ready-made candy sugar crystals – I found that the best price I could find for these was on Amazon UK.

There is an element of carving required for this cake. I recommend using sturdy sponge cakes for this. A Victoria sponge or my lemon drizzle cake both work well for this, but something like a carrot cake, with all its sultanas and carrot, would be more problematic. Nothing is impossible, but make your life easier if you can.


You will need

For the Cake

  15cm (6in) and 25cm (10in) cake tiers, covered in white sugarpaste

  20cm (8in) double-height cake, filled and chilled

To decorate

  1.5kg (3lb 5oz) white sugarpaste

  100g (3½oz) royal icing

  100g (3½oz) each of blush and grey coloured sugarpaste

  small non-stick rolling pin

Content continues after advertisements

  piping gel

  craft knife

  granulated sugar

  500g (1lb 2oz) candy sugar crystals

  airbrush colours

  gold lustre dust

  bronze lustre dust

Assembling and covering the cake


  • The 15cm (6in) and 25cm (10in) tiers should be covered with sugarpaste as normal and set aside while you work on the middle tier. This 20cm (8in) tier should be double-height to allow the space to work in. Split, fill, crumb-coat and then chill the cake for at least 1 hour to enable you to carve effectively. I took a simple slice out of my cake – cut a triangle so the geode formation is deeper in the middle.
  • Spread a small amount of buttercream over the cut cake that is now exposed and cover the tier in white sugarpaste. If there are to be any creases in the sugarpaste (this is a tricky job!), make sure that they go into the carved-out area, as this will be covered in crystals and completely disguised.


  • Leave your covered cake tiers to dry overnight. The next day, dowel and stack the cake tiers, using a little royal icing to secure each tier in place.

Decorate the cake

  • Roughly mix together blush coloured (made using pink and a little orange colouring) and grey sugarpaste, so that they are blended unevenly with a marbled look. Roll into long strips of around 5cm (2in) width and use these to create the outline of your geode, fixing them to the edges of your carved out area and to points on the tiers above and below. I used piping gel to stick my paste, but you can use cool boiled water for this. If you have any paste that is sticking out too far from the surface of your cake, trim this down with a craft knife. Press your fingers into the outside areas of this paste to give it an organic finish.


  • Brush the blush/grey sugarpaste with a scant amount of piping gel and gently press granulated sugar into the paste. You are starting to create your geode!\


  • You're now ready to begin assembling the geode – spread the carved out area of your cake with a thin layer of piping gel and begin building a covering of sugar crystals from the bottom to the top of the shape. If you find that a crystal is refusing to stick, you may need a tiny bit more piping gel or to select a smaller crystal. The packet will contain a small variation in sizes. Leave the crystals to dry for 30 minutes.


  • Once the crystals have been set, you are ready to paint. Choose any colour that you like, but ensure that you have a high alcohol content in your colour, so that they will dry quickly and not start to dissolve your sugar crystals. Mix any blossom tint colour with plenty of vodka for a quick paint. Airbrush colours work well and I used pop pink with a little sunburst orange by Squires Kitchen. Always start from the centre to concentrate the deepest colour there and, with a scarcely loaded brush, stroke out towards the edges.

Finishing touches

  • Because I love pyrite (or fool’s gold) and think it is quite festive, I have added a small detail of this. Naturally occurring in rose quartz, these pops of sparkle feel rather festive to me! I have achieved this by dabbing a scant amount of gold lustre dust at random points inside my geode. The lustre will adhere to the painted crystals.


  • I have edged my geode with a little bronze lustre mixed with piping gel to make a nice thick paint. By dabbing this paint into the very edges of my blush/grey sugarpaste, the whole Geode is given a lovely outline.

This tutorial is exclusively from Charlotte White at Restoration Cake and is exclusive to Cake Decorating Heaven.

More in On Trend Techniques

More in Cake Decorating Techniques

Click here to view our range of subscription offers!

Click here to view our range of subscription offers!