Halloween Fault Line cake

Halloween Fault Line cake

This deliciously spooky 4-layer halloween fault line cake will keep everyone horrified this Halloween. My gruesome guide will take you through every stage from marbling sponge, modelling zombie fingers, creating a buttercream faultline, conjuring horrifying evil eyes and painting bright red 'blood' onto shards of 'glass'. 


Make TWO batches of cake mixture and colour one bright red and the other bright green


Ingredients for one batch of cake mixture:

4 eggs

250g caster sugar

250g margarine or softened butter

250g self-raising flour

red food colouring

green food colouring


Ingredients for the buttercream

750g salted butter (softened)

1kg icing sugar

green food colouring

grey food colouring


Decorating ingredients

10-15 Fox's Glacier Mints

250g black ready-to-roll icing

100g white ready-to-roll icing

small amount of red ready-to-roll icing 

175g green ready-to-roll icing

red candy melts

red food colour (gel)




Tala Large mixing bowl (x2)

Wooden spoon

Tala Performance non-stick 20cm-diameter round sandwich cake pan (x2)

Greaseproof paper

Tablespoon (x2)

Stainless steel tapered icing spatula

Wire cooling rack

Large storage tub

Medium mixing bowl

Silicone headed spatula

Round 20cm diameter cake board

Cake decorating turntable 

small baking tray

cake scraper

Mini rolling pin

Sugar Shaker

cling film/plastic wrap

Circular cutter (approximately 5cm diameter)

Tala modelling tool set

Drinking straw

Disposable piping bag/reusable piping bottle

food safe paint brush


  1. Preheat the over to 150 degrees Celsius (fan), 302 degrees Fahrenheit.
  2. Line two 20cm diameter cake pans with greaseproof paper (a circle in the bottom of the pan will suffice if you are using Tala Performance bakeware).
  3. Cream margarine and sugar until thoroughly combined. Drop in the eggs and mix again, followed by the flour, mixing to a smooth consistency. Finally add enough food colouring to achieve a nightmarishly bright red colour. Set the mixture aside for a moment.
  4. Repeat the process in the second mixing bowl, this time colouring the mixture bright green instead.
  5. When you are ready to fill the pans, mix each coloured batch briefly, then drop tablespoons of mixture in alternating colours until HALF of the mixture in each bowl is used up.
  6. Use the tapered spatula to marble the mixture by drawing a long wiggly line from left to right, then turn the tin 90 degrees and repeat (resist the temptation to mix any more than this, as it will muddy the colours)
  7. Bake for at least 40 minutes until the cake is well risen and springy to the touch. Remove from the oven and allow the pans to rest for five minutes before turning out and allowing the cakes to cool fully.
  8. Repeat the filling process with the remaining cake mixture so you end up with 4 cakes in total.
  9. While the cakes are cooling, make up the buttercream by creaming the butter and icing sugar until pale. Transfer it all to a large storage tub or covered bowl.
  10. Place approximately 750g into a medium size mixing bowl and colour it green, mixing carefully with a silicone headed spatula to ensure there are no streaks.
  11. When the cakes are cool, cut off the larger part of the dome with a cake leveller ensuring that each is the same thickness.
  12. Use a couple of dabs of buttercream to secure the flat side of one of the cakes to a cake board, then roughly divide the icing into three and spread a third over the surface of the cake, placing the next cake on top and repeating until the final cake is placed, flat side uppermost, on top. Chill for a couple of hours if you have time.
  13. Using a large breadknife, trim the sides of the cake so that the diameter of the cake is slightly smaller than the cake board it is sitting on.
  14. While the cake is chilling you will have time to prepare some 'glass' shards to put on top of the cake. Preheat the oven to 150 degrees Celsius (fan). Take a small baking tray and line with greaseproof paper and place the mint sweets into the middle of the tray. Place in the oven for about 7 minutes until they fully melt. Remove and allow to cool.
  15. Reserve 200g buttercream and colour the rest grey. Place the cake onto a turntable, if you have one and roughly plaster the sides and top of the cake with buttercream.
  16. Use a cake scraper to smooth the sides of the cake by holding the scraper with one hand while spinning the turntable with the other. The sharp edge of the scraper will catch the icing and create a smooth 'wall' for the outside of the cake. Chill for an hour.
  17. Dust the work surface with icing sugar and use the mini rolling pin to roll out a flat sausage of black ready-to-roll icing long enough to encircle the cake, as shown. (Save a little bit for making the eyes, eyelids and fingernails later.)
  18. Apply the grey buttercream to the sides and top of the cake to just above the top of the black strip. It need to be applied in a layer thick enough to reach the diameter of the cake board at the bottom as this will be our guide for smoothing the icing in a moment.
  19. Apply more buttercream to the bottom section of the cake just up to the bottom of the black strip. Then use the cake scraper, this time holding it below the cake board so that you make a nice smooth wall of buttercream that is flush with the board. The scraper won't be tall enough to smooth the top part of the cake at the same time, so you'll need to hold it up and keep it vertical while you spin the turntable with the other hand. Smooth any peaks of icing that form over the top of the cake with a mini palette knife.
  20. Colour the remaining buttercream a darker grey and apply to the cake here and there to create a two-tone effect like mottled concrete. Smooth afterwards with the scraper.
  21. To make the eyes, roll out a very thick (2cm) piece of white icing, cover loosely with cling film (plastic wrap) and punch out a round, domed circle. Repeat.
  22. Attach to the cake with a little cooled boiled water so that they seem to peer out from the fault line.
  23. Prepare the red irises of the eyes by rolling out the red icing in the same way, though this time not so thickly. This time cut out using the 'wrong' end of a small icing tip. Attach to the white eyeballs with a little cooled boiled water
  24. Roll out black icing and use the round cutter to make eyelids, as shown. Attach to the eyeballs to created a hooded evil eye effect!
  25. Create horrifying zombie fingers by cutting the green icing into 16 pieces. Then cut about 5 of those pieces in half, so that you end up with big and little fingers. Roll each piece into a sausage shape and mark crease lines with a modelling tool (or sharp knife). Impress the shape of the finger nail with a drinking straw. Then make the nails by rolling out black icing and cutting out circles with the tip of the straw. You can cut them to create a ragged effect if you want to.
  26. Attach the 'fingers' with a little water. They will stick best to the black strip. Try to bunch them together and bend them slightly at the knuckle so that they look like grasping hands!
  27. Melt the candy melts according to the instructions on the packet and transfer to a piping back. Pipe drips from the top of the cake and dripping from the faultline.
  28. Carefully smash the melted mint sweet 'glass' and poke the long shards into the top of the cake. Paint blood-red drips with red food colouring gel (mix in little water to get some really gruesome drips).
  29. Use the same red food colouring to paint some detail into the eyeball, some lovely red veins and some general red streaks here and there.
  30. To finish, cover the foil edge of the board with a length of black washi tape.


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