Trend Alert: Geometry Cake Design

This week we have a handy tutorial from Charlotte White on how to create an easy geometry cake design for your bakes. Very modern looking cake...

This week we have a handy tutorial from Charlotte White on how to create an easy geometry design for your cakes.


You will need: 
For the cake:
  • Two 15cm (6in) square chocolate cakes of approx 7.5cm (3in) depth each
To decorate:
  • Chocolate cheesecake frosting (recipe on my website)
  • Chocolate ganache 300g (10oz) - dark chocolate and 200g (7oz) unsalted butter)
  • 25g (1oz) Gold Flexi Ice
  • 15cm (6in) square cake drum
  • Side scrapers (large and medium)
  • Geometric Cubes Flexi Ice Mat
  • Large metal palette knife
  • Small palette knife
  • Chef’s blowtorch
  • Side smoother
  1. Your first multiplication will be to bake two x 15cm (6in) square chocolate cakes. To make a cube, the height of your cake will need to be equal to its width, so your cake will need to be 15cm (6in) tall. Allow your cakes to cool completely.
  2. Split your cooled cakes into layers of approximately 2.5cm (1in) depth each and assemble on a 15cm (6in) square cake drum with Chocolate Cheesecake Frosting. Again, the recipe for this is free on my website but you can use any chocolate frosting that you like. I found that, with the added height of the cake drum, I only needed five layers of cake to reach the 15cm (6in) height that I needed.
  3. Cover the top and sides of your cake in frosting. Start by spreading a generous layer, more than you need, with a large palette knife.
  4. Remove the excess frosting from the sides of your cake using a large side scraper. Press the scraper gently against the straight edge of the cake drum beneath your cake and use this to keep a perfectly straight line. You will find it easier to preserve the sharp edges of the cube if you scrape each side from the edge to the centre of each side each time
  5. Repeat step 4 as many times as required until you are happy with the sharpness of the edges of your cube.
  6. Scrape the excess frosting away from the top of your cake by laying a cake scraper flat against the top edges and dragging in towards the centre. Dragging the scraper inwards from the edges will preserve their sharpness.
  7. Once you are happy with your covered cube, refrigerate for 1 hour or freeze for 30 minutes
  8. Prepare a dark chocolate ganache by melting dark chocolate in a bowl set over a pan of gently boiling water. The water should not touch the bottom of the bowl and you will only need around 2.5-5cm (1-2in) of water bubbling away to produce sufficient steam to melt the chocolate. Once the chocolate is melted, add unsalted butter a few cubes at a time until all is incorporated.
  9. Take your bowl of melted ganache off the heat and allow to cool to around 30 degrees. If you do not have a sugar thermometer, I would allow the ganache to cool for 10 minutes before using. You want the ganache to be runny, but not piping hot.
  10. Remove your cube cake from the fridge or freezer and stand it on a cooling rack, set on a clean tray or baking sheet. I cannot stress enough how important this is!
  11. Pour the ganache in one go over the top of the cube cake so that it runs quickly down the sides of the cake. Because the cake is cold, the ganache will set almost instantly so you are working against very short time. Do not be timid – pour that ganache like a baker possessed! You see why I stressed the point about standing the cake safely over that tray?
  12. You may find that some areas of the sides of the cake have been missed – these areas can be patched by scraping the ganache from the tray back into your bowl and pouring once more over the cake, focusing on the areas that have been missed. You will have to work quickly!
  13. If you find that there are any areas of the cake which look lumpy or where there are obvious lines of ganache dripping down the sides, these can be smoothed out with a hot palette knife. I heated my palette knife with a chef’s blowtorch, but you can also achieve this by dipping your metal (important!) palette knife in boiling water for a few seconds.
  14. After a few minutes, your ganache will be set and the cube cake can be lifted from the cooling rack. Trim away any tattered bits of ganache from the bottom edge of your cake with a sharp knife and set the cake on a serving plate.
  15. Flexi Ice is embarrassingly easy to prepare – simply measure 25g (1oz) Gold Flexi Ice into a bowl (I used one with a plastic lid to keep it airtight while I worked) and mix with 37ml (1¼fl oz) water. This looks like a very small amount but was ample for my cake with none wasted. Mix for 2-3 minutes with a small palette knife or spoon. That’s it.
  16. Spread Flexi Ice into the Geometric Cubes mat with a small palette knife. Ensure that the gold paste has been worked evenly into every part of the design and scrape away the excess. Any excess can be returned to the bowl and used again.
  17. Place the Flexi Ice mat on a baking sheet and dry in a low oven at 70 degrees for 15-20 minutes. Check the lace after 15 minutes – you will know it is ready when it lifts easily away from the silicone when flexed.
  18. Remove the lace from the mat by turning upside down onto baking parchment and peeling the mat away from the lace – never pulling the lace out of the mat.
  19. Repeat steps 16-18 a further four times to create five lengths of gold lace.
  20. Trim panels of lace to fit the sides of your cube cake and affix by very gently melting the ganache coating. I gave my cake a tiny bit of heat from my chef’s blowtorch but, again, this could be done with a hot metal palette knife.
  21. Press the gold lace gently against the sides of the cube cake, flush against the bottom edge, and ensure that they are straight by pressing gently with a side smoother. Repeat this process around all four sides of the cube.
  22. Use the remaining gold lace to build onto the lace around the bottom edges. Trim the bottom edges of the remaining lace so that it creates a seamless finish when set above the lace already on your cube cake. This may feel a little like working on a jigsaw puzzle but the final result is well worth the effort.
  23. Serve this very simple, very modern looking cake with a sense of smugness that you have totally cheated your way through geometry and presented something truly stunning!
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